Leisure Pro is my choice for gear on the internet and they also happen to be my LDS. If you read the section of the website that covers warrantees, you will see that they provide matching coverage for ALL equipment. No, you're not going to have a ScubaPro (Aladin)/Aqualung (Suunto) technician servicing your computer. However, they have some excellent technicians on staff that do the work on site and have been doing so for years without problems. I have purchased two wrist computers from them and have had no issues when I need service or replacement.
There's no techincal reason why you shouldn't buy from LP. That said, there are advantages to working with an LDS that's just a quick drive away. A good LDS provides extra services (training, group dive trips, loaner gear to try, etc.) that you just don't get from internet only shops.