Steve having run many of both, they are both pretty good engines. The FP's are built using some older mfg. methods and they seem more 'solid' if you know what I mean. Still, the LA's seem to run just fine in every application I've used them. Neither series are high performance but the FP's will run for decades and I'm betting the LA series will as well. I just finished a Primary Force ARF I got for Christmas and put an FP .25 in it. Haven't flown it yet (maybe tomorrow or Monday) but the engine has been in quite a few planes and always runs.

Rick H.