Why are they worried about a VP prop? It (almost) eliminates the risk of an expensive overspeed, leads to easier aeros and gives better takeoff performance - all for just a small increase in complexity. Is it fear of the unknown?
When we were looking for an aerobatic aircraft for club use I looked at all the certified types, this list is based on memory so I may have missed a couple:
- Cessna Aerobat - cheap but dreadful to fly and fixed pitch
- Z242 - nice but they had operational limitations at the time
- T67C/M - nice, slowish roll rate
- R2160 - didn't like it, fixed pitch and I don't think it was approved for flicks
- Cap10 - very nice and able but fixed pitch and doubts about survivability in club usage: stepping on flaps, wood/fabric, gear attaching to spar
- Decathlon - able but it's just not the same with the wing on top in aeros, especially from the back seat
- Bulldog - nice handling, wide appeal, metal and a good all round compromise
- Pitts - very able and precise handling but doubts about survivability in club use because of the landing "challenge"
- Extra - too expensive and too big a step
The "also rans" were: Pup, Citabria, Chipmunk, Z512, Moth, Stearman, Fuji - all are either not fully aerobatic or have big limitations.
If you don't need a certified aircraft then there is a much wider choice including all the homebuilts (RVs, Acrosport, Starduster, Eagle, etc) and ex-mil (CJ6, YAK52, etc) but concerns about maintenance or fuel consumption may rule these out for club use.
HTH
HFD