Agree with all of the above apart from I haven't had experience of lots of examples.
The .22 Lightning I bought about seven years ago did seem accurate enough.
The experience I had with the .177 I had back in '88 would substantiate your comments re .177 vs .22, and pretty much as you'd expect when comparing efficiency and taking into account the relatively high power output for such a lightweight springer.
And, yes, an old shooting friend of mine who was mainly into shooting .22 rimfire but also FAC air, always spoke very highly of the .22 barrels and often used them for one-off projects.