So, I'll preface this review by saying that I've always had a problem with the trash costs in this game. I truly believe that when Whizzard was released in the very first data pack, he created a problem for the game designers, one that they recognized. He basically got an auto-win versus asset-spam decks and so to compensate for this, I believe the designers started increasing trash costs. This didn't fix the issue. Whizzard still had an easy time against asset-spam but every other runner had an incredibly hard time. (I think a similar problem, that of tag-n-bag existing alongside tag-me, has been termed rock/paper/scissors. You've already either won or lost as the match begins [with only a little exaggeration].) I remember playing many nightmare games against NEH and Gagarin, but even recently I watched a game where a René with a Scrubber out couldn't keep up with a CtM and I thought that was very sad. Now Whizzard is no more and that's a good thing, but many cards with trash costs above what they should be still exist and will until they rotate out. I sincerely hope that those taking on the role of designers now will start to lower trash costs on new releases if only by a little bit.
Enough about that.
Arella Salvatore is quite a powerful upgrade. At the basic level, once she is rezzed, she will save you 2s and 1 each time you score an agenda from her server. Nice indeed! While somewhat different, her effect makes me think of the Astro-train of yesteryear. Let's discuss her pros and cons while also comparing her to a similar upgrade, SanSan City Grid.
Pros
High trash cost. As you may have guessed from my introduction, I think it is too high. I think a good rule of thumb to follow going forward is: if it is super powerful, it should have a lower trash cost (like Oberth Protocol).
Compared to SanSan, the rez cost is quite low, at only 2s.
She is very versatile.
Her obvious use is that of facilitating the scoring of agendas. Score a 2/1 or anything else in her server and you can get a 4/2 locked and loaded for next turn. And then do it again and again.
- You might actually score two agendas in one turn! If you loaded a Project Beale last turn, you could score it along with a 2/1 and then get another 2 pointer ready! That's right, her ability is a "whenever, not a "once per turn". But what if you don't have the next agenda in hand?
She can install anything! You might install a piece of ICE saving a and several s if you've got a deep server thanks to the "ignoring all costs" clause. You'll get an advancement token on it to boot. This will benefit advanceable ICE but could also potentially be used to work your way towards a job on Mars.
You could install an asset or an upgrade and advance it, even if it is not advanceable. The runner will have no idea what is going on. He or she will need to try and run the server anyway to trash Arella. If you don't have the agenda in hand or if you are confident that they'll breach the server, install a Prisec or Urtica Cipher or NGO Front or something fun.
Political Operative will trash her but not before you get the one use out of her.
Cons
While not a region, she is unique, so you can only have one of her rezzed. I think we're all glad that this is the case.
Unlike with SanSan you won't typically score agendas the turn you install them unless you add other cards to the mix. This is good and bad. Good because Clot doesn't hamper your game plan but bad because the runner has a turn to react.
The influence cost is pretty high at 3 pips. I think this is where it should be.
Councilman can stop her, though it'll be expensive since the runner still needs to trash her later.
And I'm certain there are other notable interactions worth mentioning but I'm not as familiar with the card pool as I used to be. In conclusion, this is an amazing upgrade. Because of her versatility, I consider her to be better than SanSan, which is a rather significant statement. I wish it had a trash cost of 3 or 4 so that she would be easier to snipe out of R&D or her remote server.