In our environment we are running the Dell 1855 Blades and haven't run into any problems. Next year we will buy the 1955 models.
It looks like I'm going to be moving into the land of Blade servers. We're a Dell shop, so Dell 1955's are what is being looked at right now. I want to put together a host list of key items to make sure these things have/support. Memory backed RAID cache and power issues are the only thing I have on the list now, since that was the main issues I've seen come across the list. Obviously, management of the blade chassis is important.
If it's useful, here is what we are planning to do with the Blades: There is no intention of moving our Citrix farm to blades, but we are deploying a new business level app using VMWare ESX3. This new app will utilize web servers and SQL servers. The web farms will be in ESX and will utilize an application load balancer, the SQL servers (starting with 1) will likely not be in ESX, but that is undecided.
We will have a fiber connected SAN as well, but the plan isn't to boot off the SAN (right now at least). It is unknown if we will connect the entire blade chassis to the SAN, or servers individually. It depends on the cost of the fiber switches.
We are doing a lot of server consolidation as well to 2 existing 2850 (dual 3.4ghz Xeon's) running ESX3. As we need more capacity, we will use additional Blades for ESX 3 and consolidation.
The 10 blade chassis specs out to about 6k. Each 3ghz Dual Core (woodcrest) blade with 16 gigs of RAM, 2x75gig SAS drives and dual Broadcom TOE GigE/dual QLogic Fiber HBA's will run us about $6600 (including warranty/support)