I am a "member" of several clubs. Learned how to fly on an OS 40 LA, the definition of easy. Learned how to needle on an OS 40 FP and OS 46 FX. Learned how to replace bearings on an used Mag 61 Pro which flat screams. Got a very strong TT 40 Pro because it was only slighty more than an OS LA and learned about being open minded and what value means. Won an OS 46 AX and it is a joy.
Re-learned about bearings in used engines in an OS FS 90 (20 plus years old) as well as how to make gaskets etc.
Learned how to run fourstrokes with an OS 70 Surpass, used of course but a strong strong engine. Picked up an OS 70 Surpass II because I liked the Surpass so much and yes it is a VERY nice engine.
Fell for the very pretty Saito 91. What can I say. It runs strong, sounds good and to me "looks" like what and airplane engine should look like.
Re-learned about value with my Magnum 91 four banger which pulls nearly as hard as my very cool saito with barely any more need for tuning etc.
Just picked up a Magnum 120 4c for a Cap 232. I learn slow but two leasons in value seems to have been enough.
None of these engines are perfect. They all have quirks. But they all have benefits too. If I had all the disposable income I could wish for I would have a Packard Merlin if you know what I mean. As it is now I do not need the all out top fuel experience which is YS, I still drool for Saito engines. OS is one fine line of products and I harbor no ill will toward them. TT and Magnum are solid engines in my experiences both as an owner and watching fellow flyers at my field. The money saved per engine (OS 120 vs Mag 120 4c) will buy me a lot of fuel for next year.
Just my humble $0.02
Eric