Heh, good question really.
When i was looking for a new mobo, i considered both.
In fact, the MSI was my first choice, but the store i wanted to buy from didn't have it in stock, so the A8n32-SLI Deluxe became my motherboard.
Last i heard, the MSI still seemed to have a HTT max of around 300, which is disappointing.
Even though i think Asus has been pumping out alot of crap mobos lately, i'd say the A8N32 is slightly better than the MSI overall.