I have owned and run a number of O.S. LA-series and Thunder Tiger GP-series engines. The .25 LA is a terrific little engine, as is the TT .28 GP. I think the TT .42 GP makes a better sport engine than the .46 LA, but I like the .40/.46 LA on trainers because the top rpms aren't as high as the GP .42. The .65 LA and .61 (65) GP are both terrific engines well suited to a variety of aircraft.
I am a fan of the Hobbistar Select RTF trainer that normally ships with the .65 LA on the nose. It is currently listed as temporarily unavailable, so it will be interesting to see if Hobbico updates it. Perhaps they'll bundle it with a lower-cost .65 AX like they did with the new Avistar Elite RTF and the .46 AX II? Only time will tell.
Maybe I'm getting pessimistic in my old age, but I'd be more likely to bet that they're simply getting out of the .60-size trainer market... such a shame.