I understand your sarcasm about the cheeky note.
Some Clarification, hope this helps:
1. Untested Fan Design. By untested I mean untested over time. This is a new fan design from HP, derived from a toy airplane engine (according to HP), with no precedent for fans tested running at 10,000 to 18,000 rpm over 3 or more years 24 hours a day 365 days a year. IBM Blade blowers were used in mainframes and large Unix servers for 10 years before they ever went in to the blades.
2. By pClass blades being worthless, I mean try to trade them in or get a good lease rate on them. Not that HP won't charge you full price for them, but that you cannot get any trade in money out of them once they are retired compared to the IBM blades because of the design change. This change increases lease costs and lowers trade in value. Street value for a stripped (no memory or hard drives) used pClass blade is about $40 US, used IBM blades are about 10x that.
3. By power anomalies. As power supplies are loaded up and down by switching them on and off they become more and less efficient rendering it difficult to measure and accurately predict power efficiency levels in data centers because the efficiency changes. Data center power administrators hate this stuff. Additionally this repeatedly heats and cools components within the power supply expanding and contracting them making them less reliable. Better engineering would yield a more efficient power supply not needing to be switched off and on or quiesced to make the total solution more efficient.
4. Someone mentioned "Backward compatibility doesn't count unless you can actually turn the blades on !!." All IBM blades and switches ever produced will work in the new chassis, so not sure what you mean by this. Additionally all blades currently shipping will work in the old chassis providing you do not exceed total power levels supplied by the chassis which is fine for customers who have a few empty slots left in an old chassis populated with old servers and need to add a few more new servers. They are backward compatible, but you have to be realistic.