Currently own a 135, have test driven a 1635, 1648, 1652 and 1660 Cab. All very nice machines. I was surprised how little difference there is in size between them considering the difference in HP range. All turn very well, seem extremely well engineered (steering cylinders behind front axle, good ground clearance and heavy castings etc), great visibility, plenty of Hyd flow and pressure (gravel pile at dealer). The ergonomics are great and seat is quite comfortable (6' 1" / 230 lbs). Whether the three or four cyl, they're all quiet. The 1635 qnd 1648 were both HST, very nice to drive and extremely quiet. The 1652 was power shuttle, also nice, and the 1660 was Dyna QPS, WOW! Would have to say I'd take the Dyna over an HST on a tractor in that HP range, smooth transitions and incredibly easy to use.