Paul outside of youself and Intel some would say that there are concerns with IPFs sustainability and longevity. Only time will tell.
No, I would turn that around and say such concerns are largely confined to a few detractors in the trade press and AMD fans. The former are fuelled largely by whispers in the ear by those in the industry most threatened by IPF. The latter is simply to be expected because IPF represents an important path taken by Intel along which AMD is unable to tag along for a free ride.
It is a description of the five device 90 nm chipset for the Fujitsu PRIMEQUEST. The level of investment and effort here makes Horus and Cray's STAR ASIC look like a joke in comparison. That is just one IPF OEM. HP has two new sets of IPF chipsets, SGI has its new SHUB2. Hitachi, NEC, Bull each have their own IPF chipsets and so on.
Web forum types like you and I can debate this all we want but it is clear Intel and its seven major IPF OEMs (and many more minor ones) along with major ISVs of high end business and technical apps have made a huge investment in IPF silicon, hardware, and software and it is showing with quarter after quarter of rapidly growing sales and market share. This year IPF will likely easily grow past SPARC and PA-RISC and push sales to $4B+ and 20+% market share.