There’s some debate on how you define a true L2, but I’d say Lightning is the only one that really qualifies. All the rest have very different trust tradeoffs.
Stacks is an affinity scam as far as I can tell.
Ark is promising (still in development) and probably has the best trade offs.
I also think Alpen (from Alpen Labs) and Spark (from Lightspark) are interesting.
