In most factions it´s simple. You need a code gate, you take Enigma. Not because it´s overpowered or exciting, it simply does not have any competition.
In HB you actually have alternatives, but browsing decklists from worlds I still see Enigma in almost every deck. I believe that´s wrong, but I´d love to hear your opinion. Below are my opinions on the cheap HB code gates.
Turing
Probably the best choice from the bunch. It´s quite week on centrals against non-Faust decks, hence I´m not entirely sold on 3 copies, but everyone seems to agree that 2-3 are very good in the current meta.
Viper
The tracing Enigma. You sacrifice a hard ETR for a very good rez-pass cost ratio. A good deal. The biggest downside is 4 str: it makes the already substantial weakness to Atman 4 even worse.
Viktor 1.0
Eli´s forgotten, inferior brother. Downsides are obvious: it´s clickable and weak to Yog. With CVS around Yog is not much of an issue these days. What´s worst is that one BD is a price runner will gladly pay on important runs. There are also a lot of upsides. It does punish facechecks better than Enigma does. It is strong against Atman 4. And it is more expensive to break, requiring a boost from Faust, Gordian, Refractor and Faust. This one is my personal favorite.
IQ
Very cool with it´s flexibility: you can try to play around Yog, Atman, D4vid, whatever is the threat in the matchup. Sometimes you´ll even be able to rez it cheaply with few cards in hand. Even without it gives reasonable stats for ist costs.
Next Bronze
Obviously synergizes with NEXT Silvers, but is not terrible on it´s own. It´s 1 cheaper than Enigma and does not have Quandary#s weakness of insta-dying to Parasite. That being said, omnipresent Parasites are what keeps it from being the best cheap code gate in the game.
Quandary
Even though it theoretically ends the run, it doesn´t really stop Anarchs and their Parasites, which makes it unacceptable for me.
Enigma
By all means solid, but it is in the 2str sweet spot of most of the decent Decoders (and Faust). The first sub sometimes prevents the runner from mustering enough resources to get through a server. However I don´t feel that it is better than it´s less straightforward alternatives.
My personal preference is 2-3 Turing, 2 Viktor 1.0, 0-1 IQ. 1-2 Tollbooths on top of that obviously. I´m curious what is your take on the cheap HB code gates. Discuss!