Both chassis makers used the side radiator in the 40' Bus. The Phaeton carries a rear radiator. I had a 40' 2008 Bus and loved it. We ran it almost 75,000 miles before we turned it in on the 2013 this January. When we bought the40' 2008, I drove the Tiffin Allegro Bus with their Powerglide chassis as well as the Spartan and Freightliner. I picked the Freightliner as it had a firmer, more steady ride than the others. My criteria was a high speed lane change, a low speed hard turn, a maximum brake stop from highway speed and the overall feel of the ride. The 2013 is only produced in the Tiffin Powerglide chassis, but it's superb. We have 22,600 on it and have had it through the frost heaves in Yukon and Alaska and it was way better than the 2008. A vast improvement.
2013 Tiffin Allegro Bus 43QGP
2011 Chevy Silverado 1500 Toad