The Super Nova is basically a Nova 700 on crack - this review covers both pretty much - I've owned several of each.
The Supernova came stock with a .45 frame, 700's with an M16 grip. SN's were all black in color as opposed to the heavenly ano the 700's had(although there were limited color runs, I know I've seen purple and blue, but they are pretty rare). SN's also had a regulator/asa attached to the gripframe and D-icer beads to help run better on Co2.
That aside, lets get to the good stuff...
Performance - The Nova line in general was very innovative in its design. It was the world's first totally pneumatic paintball marker...even the trigger was pnuematic. It runs with an extremely efficient spool valve design(which I think was the first marker to use a spooler) and functioned very well on co2 and HPA. The pnuematic trigger is a slider, not a traditional hinge design and with some practice, you can get into a very fast rythm with it. It is a large marker and somewhat heavy, but not uncomfortable and pretty well balanced. Oh, and these are QUIET. I mean very, very quiet. It runs on 95 psi and is very consistant shot to shot. They also use an intersting barrel design. It articulates so there is no bolt, so to speak. This makes it extremely accurate, proabbly the most accurate marker I've ever used.
Reliability - There really isn't much to these markers. It's just a couple pieces and a bunch of orings. I've had a few over the years and the only problem I've had were oring related. Not a hard fix at all BUT some of the orings are odd shaped, and you might not be able to find them at your local hardware store.
Cons - Lack of support, there is no more Airstar. Also the Orings are odd sized and not super easy to locate. The only other thing is the size, it is a BIG marker.
Overall - It's a great marker that was super innovative in the day and it paved the way for the matrix and other spoolers. A very nice head turner to take to the local woodsball field.
Supernova:

Nova 700:
