as for customer service, all web-based companies are similar, but I would think Dell is better, Tiny is very good value for money, but customer service is not the strong point.
for you requirement, you need to go for the Top of the range.
Eversham and Rock, both have very good top of the range Laptop for your requirement and their services are definitely better than Tiny (I was told).
If your money is tight for Eversham and Rock, give AJP a try. They have great laptops. I used two AJPs and they are still going after 6 years.