From my experiences buying a rib last year when we went to the boat show (southampton 2002):
Ribtec (what we intended to buy) - werent really interested in selling us a boat. From my experiences with a friends ribtec, the ribtec deep-v hull is excellent (as used by Alan Priddy in his round the world trip).
Tornado (whose stand we visited) - the salesman (Laurence Lock from barnet marine) was able to show us all the options, and give us a firm price and spec of what we wanted, and showed a good understanding of how to rig a boat for what we wanted to do with it (diving). We ended up buying the tornado (actually the voyager hull), and it has been great. Build quality is good, and the fittings are all solid and made to last.
The voyager hull is designed to give lift, and doesnt have as good a deep-v as the ribtec, but still handles big sea with no problems. The only thing that is a problem is the nasty solent chop which tends to make the boat bang around a bit (steep small waves close together.)
hope this helps,