Speaking generally, there's nothing more subjective in evaluating bikes than matters related to comfort. All the contact points - between you and the bike (saddle, bars/grips, pedals/shoes), between the bike and the road (i.e., tires) - as well as any suspension elements fall into the one-man's-meat-is-another-man's-poison category.
So, subjectively: I've ridden a Downtube full suspension heavily and am now using a Xootr Swift as my main ride. I prefer the unsuspended 20 incher as long as it has my holy trinity of comfort: Brooks saddle, Ergon grips, and Big Apple tire in front. These might not work for you, but, for most people (assuming the bike fits you properly) choice of saddle, bars/grips setup and tires will have the biggest impact on comfort.
Suspension can definitely make the bike more comfy, but keep in mind: all other things being equal, suspension adds weight, cost and maintenance to any bike (as well as pedal bob, which may or may not bother you). And on cheaper bikes, with cheaper suspension elements, it adds components which will degrade in performance quickly and will need (sometimes expensive) replacements down the road.