Advantages: Highly trusted brand, easy to overclock, its quad-core and it has a good amount of L3 cache
Disadvantages: requires a compatible motherboard and at least, dual channel ddr3 ram
I bought this processor with a p7p55d evo motherboard from ASUS and two sticks of corsair ddr3 dominator dual channel ram, and together I have seen a huge improvement over my old core 2 duo set-up.
2.66 GHz may not sound like very much compared to 3.4 GHz from a Pentium 4, but it's quad-core, meaning it's actually about 10.6 GHz. Also, this processor is a beast for over clocking, with aftermarket air coolers easily and safely breaking 4 GHz and beyond. I have never over clocked before, but got this up to 3.2 GHz per core easily; I am sure that people with more knowledge could go further. In addition some motherboard manufacturers have easy to use software that makes overclocking easier, like ASUS's TurboV EVO.
It gets a rating of 7.3 in windows 7 system rating at default speeds, and can easily run any normal program, and performs very well in games. It runs very cool with both stock and after market coolers, and comes with the stock cooler in the box, with thermal paste already applied. It also comes with an Intel i5 sticker, which is a nice touch. But I would recommend purchasing a third-party CPU cooler as this will increase the life of the processor.
Summary: Overall this is a very good processor, and i would recommend it to anyone who is interested in an affordable but powerful processor.