I think most people will recommend the mStand, as it's very sleek and efficient.
Personally, a stand is a stand for me, and I didn't want to spend that much on it so I got the Griffin Elevator, which you can grab new off ebay for $20, half the price of the mStand. It has an open bottom so it will dissipate heat from your MBP just fine. It also doesn't look that bad, just not as attractive as the mStand.
If you have the money and care about looks, definetly go for the mStand. But if you just want functionality and a good value, the elevator's your best bet.