Your sleeping style is probably the most important thing to take into consideration here. My partner (a hard core side/front sleeper) and I have 2 full length Stephenson's DAMs @ around 24 oz each. This should be the ultimate lap of luxury pad, and it is for my partner. But for me (a 100% back sleeper) I hate it. My arms hang miserably off the pad, I feel a bit sea-sick at times because of the way it wobbles when I move, it's heavy, and it's prone to punctures. The last is in theory as we've never had the problem (yet), but I always worry about going from 4 inches of insulation to virtually zero due to a leak.
My pad of choice for most situations is a Ridgerest cut down to Torso size. Or a Ridgerest of any size really, but that's as a back sleeper....