Haven't seen any serious tests yet, but mine is definitely much cooler on my lap. This is the first MBP I've had that I'm comfortable having on my lap for longer periods of time. It's cooler underneath and on top. It'll be interesting to see some more objective tests...
I'm just really interested on how much cooler it is, if it is THAT much cooler, then I would buy the new penryn and sell the SR mbp. My SR mbp gets pretty damned hot.
I dunno, mine is slightly cooler outside, but the actual processor usually runs at about the same temperature. I wouldn't say its "comfortable" on my lap after the first 30 minutes.