Ok, the first thing I will say is that Starboard haven't entirely got rid of the Evo...
The 76 Starboard Quad we tested this year was a 'convertible' allowing the option of a single fin set-up. We assumed that this was going to a pretty compromised set-up, especially considering the extra weight and four redundant fin boxes (which come supplied with blanking plates), not to mention that the board is designed for a Quad set up primarily...
However we were actually quite wrong! The board works great in single fin mode - very similar to last years Evo 75 and perhaps in some areas even slightly better?!
To be honest, in most conditions, we actually preferred the 76 in Single fin mode, which gave the board better release, a livelier ride and more predictable bottom turn.
So comparing the Quatro Tempo, I would say that that the Quatro doesnt have quite the same 'get up and go' as the best single fin boards, but is pretty close and definitely the best twin we have sailed with regard to this.
It has a very comfortable and quite directional ride in a straight line, making it great for burning around in cross on conditions and getting jumps. It also has more control than a single fin when well powered up as the board stays flat on the water rather than lifting off the fin.
In the bottom turn, twin fins take a bit of adapting to if you are used to a single fin, so you might initially prefer your old evo, but once you adapt your technique, you will find the Tempo very reliable in the bottom turn and probably a bit tighter turning. Its not quite as loose as the Rhythm, but plenty good enough for most needs in cross on conditions.
The big difference you will notice between your Evo (or any other single fin board) and the Tempo (or other twins) is the top turn. The top turn comes around a lot snappier and with less effort than on a single fin board. This is great in cross on as it allows you to get all the way around in your top turn to the point that the sail powers up again and helps link you into your next turn.
Finally, something the evo was actually pretty good at, but Twin Fins take to the next level is control in a slide. When you get a slide in your top turn, the twin fin boards (like the Tempo) seem to give you so much more control allowing you to bring it back in line or let it slide a little longer...
I hope that helps. Let me know if there is anything more you need to know for now..
Good luck with the choice!
Adrian