I'm still thinking/hoping my Craigslist OS 55 is gonna happen (the owner is in the middle of a move & is returning this week or next, when I hope we'll connect)...but I'm starting to look at options.

I'm seeing an awful lot of 4-strokes popping up, and especially at my LHS (not sure if that's cuz they're popular or if they're not selling ), so my questions are:

-Are these good for beginners? I guess I'm not really a beginner when it comes to engines...I have a lot of nitro rc truck experience...but I'd think other beginners would like to know about them, too.

-What are the pros & cons? I've heard fuel economy can be a LOT better, which would help offset the cost disadvantage...but what else? Finicky tuning? Quieter/louder?

-What's the 'conversion factor', i.e., what displacement would give me the same power as the OS 55ax?

-What brands do you like? OS vs. Saito? Are some of the offbrands good?

Speaking of offbrands...and getting back to 2-strokes...what would you recommend in a sub-$100 .50ish sized engine? JBA seems to have pretty decent reviews, so does Magnum? Thoughts? Alternatives?

Thanks, as always, to the best forum around!