I wouldn't look for anything in particular if you're only looking for a $1500 ski and just getting into the sport.. For example if it came down to a beat up Superjet compared to a real clean 750SX, I would jump on the 750. Point is, for your first ski you want a good experience and not on some beat up crap. Keep your choices open. I would stick to any year superjet or a kawi 750 in that price range. If you'd spend much more, I would recommend 96+ Superjet or an SXR. Much better platforms than the older skis. Superjet freestyle, SXR buoy racing.
Find a clean, unmolested ski. Dont buy someone's junk they beat up in the surf and has alot of hours. Keep an eye out of cracks in the hull, this will tell you if it's been abused. Check for long hours on the ski. Freshwater is ideal, but isnt a requirement buying a ski. Check to make sure the impeller isnt locking against the jet pump housing (common on salt water skis). Most importantly, water test it. It's hard when you first get into the sport and with that budget, there's alot of old beaten crap out there. Good luck and dont hesitate to link and ask about a ski.
Oh and Superjet is #1 as long as it has the 701 motor. I can't really vouch for 96+ but im sure they're good. I just bought a 08+ that is slightly different than the previous superjets. I love everything about it, awesome all around ski.