It depends on the model country clipper you are looking at. There are commercial model country clipper mowers as well. The country clipper boss is the top of their line and compares to the is3100 very well. The country clipper charger is also commercial and would compare to the is2100. The challenger is the lower commercial country clipper and would compare to the is600 or is700. The country clipper edge an wrangler are their residential models. Snapper was one of the first companies to have a single joystick controlled zero turn mower (snapper, snapper pro, ferris, and simplicity are all currently owned by Briggs & Stratton). I have seen a couple of them still running and they do ok.
Ferris will give the best ride, but the single joystick control on the clipper is great when you need a free hand to move limbs out of the way, or consume a refreshing beverage. The single joystick on the clipper allows the rider to rest his/her arm while operating the machine rather than having to hold their arms in front of them the whole time they are mowing. Another great feature on the country clipper mower is the stand up deck. Flip a couple of levers and you can literally pull on the front of the deck and stand it vertical to clean or remove the blades (Great feature). Those are two of my favorite brand mowers (hustler would be the other favorite).
I hope that helps shed some light on your question. If you want the smoothest ride on a mower then the nod would go to ferris. If you want comfortable controls and ease of blade maintenance then I would go country clipper. Both are extremely well made and offer similar drive trains. Imo you can't go wrong with either. Just looking at your bio it appears as though you already know how well a ferris rides. Which model do you have?