The CNPS7700 is big - really big. Aesthetically, it is certainly one of the prettiest coolers ever built. The device also supports Socket 775, meaning you can finally run a Pentium 570 at full load with a tolerable noise level.
The marginal enhancement in cooling performance of this unit compared with the CNPS7000 does not justify replacing the older unit if you already have it. However, anyone planning to buy a new cooler should definitely shortlist the CNPS7700, as long as it fits your board and case.
The copper version of the new cooler should cost around $50, giving it a decent price-performance ratio considering both its cooling power and ultra quiet noise levels. As was the case with the CNPS7000, the new AlCu version is a bit cheaper than the all-copper model.