Yes the PFA are a great organisation. Supporting SAFE, fun and cheap (ish) flying.
From what I know / have been told by other members. Safety is always the prime force in approving a new type. It's just that our standards are better than others. We must trust engineering to make these decisions and support them.
Yes I have heard of those who would love to build a 450hp V8 mustang replica (prowler) as an example, because they can in the states. They just can't understand why the Pfa don't argue the case for them with the Caa. Get real. If you want to fly over powered matchstick rockets or hashed together ultralights. then move to the states. cos it aint within the Pfa's remit .
As a member to I have any bad comments about engineering. Only the typical two weeks to get an email answered.
As for 'rotax' engines. I wouldn't waste my money on them. Why ? It cost me £9k to get a Lycoming 0320 good for another 200o hours. When for the same money I could have bought a 'Rotax' that would have died before it got to 1000. Just my experience of flying them when my then club bought three brand new Da20's. Two of which had to have new engines before 1000 tt. They now run new PA28's with Lycoming units and two have got to 2000 tt without problems. (they leased these planes from new, as with the Da20's).
E & OE