Fully agree that the IRF510 is O.K for amateur radio use. It can do the job and is very cheap.
Only one word of warning.... buy them from a reputable source that has branded devices. There are a lot of "fake" or sub-standard IRF510's around. There are some very cheap 70w RF amps on fleabay. The IRF510's they supply with the kit may even have the part numbers ground off. Throw away the supplied IRF510's and buy some known good ones, the rest of the components in the kit are O.K.
Reg ? ? ? ? ? ? ? ? ? ? ?? G4NFR?