Wildcat, you will find both of your choices to be the cream of the crop when it comes to a luxury coach. Originally I was going after a MCI or Prevost bus conversion and stumbled across a Newell by accident and been sold ever since. My first choice lays with Newell but I would not turned down a wonderful Prevost conversion if it fit the bill as well. Believe me, I love the Outlaw and Featherlite conversions and what they offer. I recently discovered that Featherlite has level floor slides like Newell and If I run into the the big money one of those could park right next to my Newell.
As far as checking over your coach, there is a ton of info already on the site that will help you out and I will dig up some links to narrow the search for you. Other than that, have the engine and trans oil analysis done, once finalizing everything and prior to close of the deal it would be a great idea to have a second opinion by a reputable mechanic and if you need help there, we can probably stir someone your way. Just holler. Check air suspension, frame rust, tire age and condition, heating and cooling system, any signs of previous major damage, for corrosion everywhere, wood rot in and around windows, basement areas, bathroom, under ice maker and so on..... This should give you a good start.
Others may have a bit more to add.