I bought this as a replacement for the stock cooler on an Intel Core-i7 920, now overclocked to 3.4Ghz from standard 2.67.
I did the install at the same time as moving the components to a larger case, so the fact you have to have access to the underside of the motherboard to fix the retaining bracket wasn't an issue. On a previous build I installed the OCZ Venetta 2 on an Intel Q6600 and it used the push pin system and was very difficult to secure - the backplate and screw fixing on this Zalman is a much better solution for large, heavy coolers, especially if they are in a tower system where gravity will constantly be trying to pull the cooler away from the cpu.
I used Arctic Silver instead of the supplied thermal grease, and using Prime95 my load core temps are in the mid 70's whereas they were previously up in the 80's - 90's.
The fan is quite noisy at it's maximum 2000rpm, but I have set it to quiet via the BIOS so in normal operation it runs at about 1000rpm (as do the 12cm case fans) and that is fine for me. It wasn't my intention to make this a 'silent' build (that's my next project !) so there may be better coolers out there if that is your intention.
Overall, I am happy because even under stress the system is stable and in normal operation it is quiet enough too.