Guess I'm still a little confused about Vertical EDGE vs Escape. I thought "Vertical EDGE" was applied to all standard '04 and '05 RMKs, but apparently it was used on '02 snowcheck sleds? I do know "Vertical Escape" was snowchecked '03 and '04s. Also, the earlier chaincase was used on all '02 and '03s except the Vertical Escape; all '04 and later used the "phantom" chaincase. The dipstick by the bulkhead sounds like the older chaincase, where it's on the right side of the chaincase down low (and a pain to get to with the stock can in there). Never heard of an EDGE RMK with a different driveshaft and jackshaft mounting, so don't think any model will fit a bigger paddle than any other.
Just did some digging through part numbers to confirm some things I've heard about the Escape. The '03 Escape has the following upgrades over standard '03: lighter jackshaft, lighter trailing arms (with only the narrower ski stance), lighter radius arms, PERC, revised chaincase, RydeFX shocks all around (ski and rear shock are clickers). Let me know if I'm missing anything. '04 Escape got all those things except apparently the jackshaft. Also, some of the Escape-only things from '03 made their way (standard or optional) to other sleds in '04. I thought I'd read that the drive shaft was different too, but part numbers are the same for all '03 and later EDGE RMKs. What really confuses the identification is that these sleds are easily old enough that there are mix and match sleds out there.
Anyway, $1500 is a great price for a loaded out sled if everything is straight and solid. On the flip side, a seemingly functional sled could have all kinds of bent and broken suspension components, crank out of true, weak compression, worn out clutches, and so on. Truly a case where someone else's basket of problems will cost you more to fix up – even if you got it for free – than what you'd spend just buying one in better shape. You're likely to find something wrong on any used sled. Big thing I'd say is if it's not either a garage queen or been obviously well maintained, it's probably not worth your time and money unless it's close to or less than $1000. On an Escape, you can make money parting it, but again, if it's beat to death then the high-value parts may be junk too. Shocks are the real big-ticket item if they're straight and the shafts aren't pitted. If that's the case, add $200 to rebuild them all, and you've got the best shocks you'll find for these. Again, buyer beware: a new shaft for the rear clicker is $150, and I'm told the hollow shafts for the ski shocks are NLA (you can put in solid shafts – you'll lose the clicker, but still have a much better shock than the standard replacement).
Well, long post, just some (hopefully accurate) information I've gathered from working on and upgrading my sled. Given how little I see even pristine EDGE sleds listed for, I think these are the best "bang for the buck" sleds out there, and a great starting point. Understandably, most people move to newer sleds when they have the resources, but that doesn't mean these are best left to the bunny slopes!