We have experienced some problems with IBM blades, both HS20 and HS40, running a fairly large 33,000 mailbox Exchange system. We have experienced some hardware failures, CPU replacements mostly. IBM has been good to work with on the hardware replacements although on one of the replacements the technician had to come back 3 times before finally replacing the motherboard to resolve all of the problems. My greatest difficulty with the blade servers has been in troubleshooting fibre connectivity issues. The fibre passthrough modules make if difficult to isolate connectivity issues. Part of...read full review »