I love builder. It is cheap to res, it is mobile, it's expensive to break, and it quickly builds up ice all over the board. This thing can make am ice wall really hard to break really quickly, and it will get your cosmic ice out cheaply. The best part is that it forces the runner to essentially help build your servers, how can you not love it?

Builder is an interesting piece of ice.

First off, 2 to rez for a 4 strength ice with 2 subroutines is totally calvinball. The basic Gordian Blade take 4 to break, and it is not immediately in Yog range. Code gates are also not really done in Weyland, so this card is a bit of an unwelcome surprise.

If they break Builder the first time you rez it you've paid 2 to make the runner pay 4ish. That's obviously great (practically unheard of for Ice), and it only gets better if they keep running it. So what's the catch? I mean, ice with a better ratio than Eli 1.0 and no bioroid click through, that's crazy.

Well, the catch is what Builder does. It doesn't do any damage or end the run, all it does is buff the ice after it by giving it 2 advancement tokens. What do those do? Depends on the ice. The Ice Wall Fire Wall Hadrian's Wall style carrds get more strength for each token. The Tyrant Woodcutter style cards get more subroutines. For ease of reference we can say that they get 2 creds tougher to break, permanently.

Still sounds pretty good, right? I mean, 2 to break a 2 rez ice is acceptable even before we consider that it can snowball. Builder in front of advanceable ice is super efficient and taxing. It can even hop from server to server! So why don't we see it more often?

First off, this is positional ice, with all the irritation that that entails. It can't defend any server on its own. It isn't even normal positional ice, it is positional ice that only works in front of advanceable ice. That means that in your deck building its hard to treat Builder as Ice, since it can't stop the runner unless it combos right. Do you slot it in instead of a support card?

Beyond that, the ice that Builder buffs aren't very popular. I've never seen a Tyrant in the wild, and typically ice wall is just quick gear check ice. Advanceable ice generally isn't played, so a buff for it is in a weird place.

I think that's where I'm putting my conclusion. Builder is great when it works, and to work it just needs you to play advanceable ice. If you are running advanceable ice anyway, by all means give Builder a try, its a better economy piece than most. But I don't think running advanceable ice is the right call, in general, so Builder isn't something to recommend.