Hello Paul, welcome to RCuniverse. I have in my hanger a SuperTigre 90 and a 51. The 90 i have in an Excelleron 90, and I cant fault this engine. It has flown my aircraft now for well over 1100 flights and still going strong. In that time I have only replaced the bearings once along with a piston ring. The 51 SuperTigre has yet to require any servicing and has performed 327 flights. So all in all , Yes I can recommend SuperTigre Engines. I am sure others will opt for OS Engines, and so they should, as i am sure they are also of very high quality, but I bought mine by price, ie they were cheaper, and also recommended by another member of our club. The Thunder Tigre i cant comment on, as i have no experience with them. So what-ever engine you choose, Iwish you many happy hours with it. Just be kind to it during the run in stages and you will do all right.
Bill