I got the premium, as the store i bought it in was out of stock of the regular. I looked at the reg, last week, and it was tiny! It's about half a tennis ball in it's stuff sack and weighs 2 oz.
As I like to read with my head propped up, and have wide shoulders, the bigger is probably better for me, but i was tempted. If I'm near the store soon (EMS), I'll blow it up get on the floor and give it a comparison test. I must say, i wasn't even tempted to put something under the premium, it was fine as is.