Being a paddle fin fan myself, I was reluctant to try on a pair of borrowed volos during a dive last month. I find split fins limit their user's finning technique and the Tigers somewhat stiff so I was wary of the Volos performance. Much to my surprise, they worked rather well. We hit strong current while diving an outer reef and I found myself pulling significantly away from my dive group; of which three members were using splits. I did several types of kicks: sculling, frog, scissors, flutter, etc. and managed to propel myself with ease.
From my experience, it seems the Volos adapt to different kinds of kicks better than split fins. Could it be its hybrid design of paddle and nature's wing technology? The only cons i can think of are:
a) The weak points on the rubber hinges can break
b) Fins' being prone to entanglement when laying down guideline
c) Some people, myself included, have to get used to its extreme bouyancy.
d) The design is just too "glamorous" for me.
For recreational diving, i think Volos are quite good. Not quite as good as the quattros or the jetfins but competent nonetheless.
Just my thoughts....