Welcome Ed,
here's my tips, do some research around the site know what your getting into, try to get an idea what will suit you needs. I'm a core wakeboard and nothing else fit me better than the SX. i did make a mistake early, i just wanted a boat found a Toyota and bought it. It wasn't bad it was a 1999 e22 need a little work but still solid. it was fun but i quickly out grew it and wanted a v drive with ballast. It wasn't the worst decision i did sell it for my than i paid, but to do it over again id just buy the SX. if your an avid skier go e21. The e22 and x22 are a nice mid point if you do a little bit of everything. some people may argue with me but i don't think the vdrives (s22 or sx) are skier friendly. I think they are made more for board sports.
If you buy during the season expect to pay top dollar. Winter or very early spring is the time to buy if your looking for a deal.
Their great boats and i wouldn't own anything else. They do have their ups and downs and their not for everybody. I would be prepared to do some maintenace and repairs on your own, unless you have an old dealer or someone familiar with the boats. Some boat dealers wont touch them. Others will work on what they know.
Good luck