The Holo Man is a powerful must-trash sysop who advances your cards for you, for a steep price. For a and 4, you can get the effect of a Biotic Labor with a 2 discount, except with the Holo Man, that effect is reusable. For fast advance decks, however, he functions a bit less like an infinite Biotic and more like a SanSan City Grid, since you need to have him installed a turn early to be able to score a 3 advancement agenda from HQ. Still, the power of being able to turn money into agenda points is not to be understated, especially since his effect comes at a much cheaper price than something like Big Deal, and he is overall much more versatile. The best thing about him, actually, is his utility in nearly any deck that needs to advance things quickly (which is most corp decks), and even in decks that do not want to score out, he is still able to pull off tricks that no other card really can. Let's take a look at (some of) the archetypes he's useful in.
Fast Advance
FA is probably the easiest archetype to evaluate his power in. In FA, it is most likely that you will be installing him unrezzed a turn early, then scoring a 3/2 from your hand the next turn if he does not get trashed. This again makes him very similar to SanSan, and they're even the same influence, so we'll start by comparing those two.
In terms of numbers, Holo Man is overall much faster, but worse long term, and carries a lot of his own risks. SanSan costs 6 to rez, three times as much as Holo Man, but also costs 5 to trash, making it much safer to leave on the board for a turn, especially in a deck that runs little to no ice. But, while Holo Man's lower trash cost makes him much more vulnerable, the runner will, depending on board state, still likely trash an unrezzed SanSan if their economy is stable. Even then, it doesn't look great for Holo Man: in that instance, you have spent a card and to cost the runner 5, which is a pretty big swing, and there's also a good chance the runner will be too poor to trash a SanSan anyway. None of this is to mention that Holo Man is significantly more expensive to score 3/2s with than SanSan, costing a and 4 every time--scoring 1 agenda this way costs just as much as rezzing a fully reusable SanSan. It should also be noted that you can just run both Holo Man and SanSan if you want, and they do stack, allowing you to score 4/2s from HQ for 5 each.
So, in that matchup, Holo Man definitely loses, at least in a deck that doesn't protect its scoring server. But, Holo Man does have some powers that SanSan does not (and yes, this is the part where his 3-advancement effect becomes relevant). In decks where Seamless Launch is a good card, Holo Man is also likely a good card for the same reasons. If you're not exclusively trying to score from HQ, and instead are playing an efficiency-based deck that tries to rush out agendas as fast as possible, Holo Man becomes a lot better and makes scoring big agendas much faster. This makes him especially good in decks that run agendas like Offworld Office, as they pay for themselves to score and will keep your tempo rolling, but still probably not better than 3x Seamless Launch, at least in PD.
I'll also give a special mention to A Teia which is able to clicklessly install him or an agenda on the runner's turn with cards like Tatu-Bola, giving you a bit more speed with your scoring. A Teia also typically has an easier time getting a lot of ice set up, which makes Holo Man a lot safer to leave unrezzed for a turn.
Glacier
In my opinion, Holo Man is decently usable in glacier and especially advancable ice decks, but in terms of non-agenda scores, falls somewhat short of other RWR cards like Business As Usual. His Sysop-ness is nice, and lets you move him to your server with Pharos on it, and at the start of your next turn, you can instantly get a fully-advanced 10-strength barrier for only 1 and 4, rather than the usual 3 3. Then, if he's survived to endgame, you can mash him in your scoring server and simply use him as a normal fast-advance tool to close out the game. He actually synergizes quite well with popular cards like Seamless Launch because his 3-advancement clause only cares about installs, not operations, allowing you to theoretically score an already installed 5/3 for a mere 2 and 5. This versatility is nice, and is what makes him in my eyes a must-trash upgrade, which in glacier, is a nice cheap prize that forces the runner through your big expensive server. Additionally, if you're playing cards like NGO Front or The Cooler NGO Front, you can use him for money... kind of? It's not actually very efficient at all to do this, particularly with NGO--you're spending a and 4 to effectively net 3, and that isn't even factoring in Holo Man's rez or install cost.
Shell Game
Now THIS is where Holo Man is most fun in my eyes. Sure, he can get you agendas from hand. And sure, he can make your ice big and strong. But better than all of this, better than his ability to get you points, is the level of magnetism he exerts over the runner's eyes. For only a 2 rez, you can, every turn, move him to any of your facedown cards: your failed traps, your Vladisibirsk City Grid, or your innocently-placed, never-advanced agendas, and the runner HAS to decide--will they check out what the Holo Man's working on? Or will they just leave him to his machinations? Typically, I expect most runners to call his bluff and run the server--after all, the corp instantly scoring a 5/3 off the table (or a 3/2 like Tomorrowʼs Headline with 2 left to punish the runner with) is a pretty scary prospect. And it makes sense: even if you hit an Urtica Cipher or Chekist Scion with 1 or 2 advancements already on it (or vs. Pravdivost Consulting: Political Solutions, that plus 1), that's still only 3 net damage or 2 tags, which sucks, but now you can trash Holo Man and you know not to run that server again. He's much easier to shut down as a confident runner, or just a runner with Pinhole Threading, which somewhat weakens his powerful Mitosis-esque mindgame abilities.
But, who ever said he could only be a lure? In fact, leaving him facedown for a turn and pretending he's an AMAZE or Mr. Hendrik or Angelique and then getting a super efficient agenda score is just as good as getting a trap hit, and can combo into some pretty powerful turns especially as NBN: Reality Plus. Or, if you're playing Issuaq Adaptics: Sustaining Diversity, you get free agenda points, which is something the runner best not overlook, and something you can use to your advantage. In a similar vein, you can use his powers and a helping Seamless Launch for a possible Neurospike kill with Fujii Asset Retrieval.
EDIT: I didn't mention this initially, but in a trap deck, you can actually keep Holo Man safe by storing him underneath an Urtica Cipher or similar, FORCING the runner through your trap if they want to trash him. This is just devious, and since Holo Man moves at the start of your turn, if the runner doesn't trash him, you can use all his sweet benefits right away.
Final Thoughts
At the end of the day, I think assigning the Holo Man as a "fast-advance" or "glacier" or "shell game" card doesn't quite express his true power. In lore, he is Epiphany Analytica: Nations Undivided's "man behind the whole thing," who has his fingers in every pie. I think this flavor perfectly reflects his gameplay: the Holo Man is always wherever you need him, and whatever you need him to be. One moment he can be efficiently building your ice, and the next he's scoring your agendas, bluffing your traps, wasting the runner's time, or just waiting for his next assignment. He's definitely a scary card to see on the board simply because of the possibility he has. His low trash cost makes him much riskier than something like SanSan City Grid for both sides, and because of that, he is, in my opinion, way more fun. While he may not have the same immediacy, safety, or efficiency as his competitors, he makes up for it with how much impact he has by being on the board.