<< I think you guys are missing the significance behind the benchmarks.
Look at the graphs on all pages. When the 1.26 Tualatin is operating on a 133Mhz bus, as tested, it beats the P4 1.8 handily in a few areas. Overclock it to a 150Mhz bus (CPU at 1.425) and not only will the raw CPU speed increase its performance relative to the P4, but the increased bus speed will give you an additional significant boost. >>
The 1.8 P4 is one of the very lowest end P4's currently available. It costs significantly less than a comparable P3, so to say that a P3 overclocked to its maximum yield compared to a P4 at the lower end of its yield is an unfair comparison. Overclock a P3 .13 micron die to its maximum yield and then use the same (or equivalent) cooling to overclock a P4 to its maximum yield, then make a comparison. Clockspeed really doesn't play any role in this, it's all about maximum yield of an architecture.
<< Stick a 1.4 in there and OC it to 1.575, and I think the competition for the P4 is stiff. The P4 might even lose, and by a big margin! Why do you think there is not a clock-for-clock Tualatin out there to compare directly against the P4? Many people suspect it is because Intel knows the P4 would lose. The P4 is simply a much less efficient processor than the PIII, especially a PIII operating with 512K of cache on a small die (the Tualatin). >>
There is no clock for clock comparison because most knowledgable people know clock for clock comparison will only prove one thing, one design has a higher IPC. That says nothing about overall speed. It's like comparing MHz among different processors, has absolutely no effect on overall speed.
As for efficiency, I think your mentality is flawed. IPC is not efficiency. Efficiency is when you utilize a large amount of the resources available to you rather than have it sit there idle. Most of the P4's die does not stay idle, in fact, I'd say it's fair to assume that the meager 2 FPU units that it has is working constantly. What resource is the P4 not using that would make it less "efficient" than a P3? It has less execution units and most of its caching is put to good use.
<< regarding upgrades - I can count on one hand (actually one finger) the times I upgraded the CPU without upgrading the motherboard too, so upgradability is a non-issue for me.
Oh yeah, and regarding the 'high price' of the Tualatin 1.4 (~$300), just look at the price of the 2.4 P4 (~$600). Which one is overpriced? >>
Considering how much the 2.4 outperforms the Tualatin 1.26 (it's not 1.4 unless you overclock), I'd say the overpricing is about the same.