I've always loved it when a quote comes directly from a customer. Here's a recent one that describes the T2000 as scary fast :)
“ Niagaras run much cooler than our previous servers, plus they are scary fast. They’ve cut our total cost of operations [TCO] through lower acquisition and management costs. The Sun Fire T2000 will be our database platform of choice in 2007. ”
— Heather Peck, Infrastructure Manager, eBay Inc.
eBay mainly uses Oracle.
You can read about it here.