I have the 7mm Steamer. It is indeed a warm wetsuit - it really seals very well and the water doesn't flush through it very much.
HOWEVER - it has what Scubapro calls a "SilverSkin" lining. It's pretty much a smooth, silverish lining on the inside of the suit instead of the normal polyester cloth found on most wetsuits - it's similar to the Henderson Gold Core coating.
I hate that lining. It sticks to your leg hair and skin like glue! I've actually taken to slopping my legs up with hair conditioner before I put the suit on.
Also, that lining makes the suit very, very weak. You can tear the inside of the suit VERY easily - and believe me, considering how hard that suit is to pull on you will have little tears all over the inside of that suit. In a normal suit the cloth lining adds strength to the suit - in the Steamer it's pretty much bare neoprene and it's very fragile.
Once you get the suit on, it's GREAT! But, just be careful pulling it on and be very careful of tearing the neoprene on the inside.