There is actually some fact to the recommendation. Sometimes users experience flickering, microstuttering, flashing, bad scaling in games, issues with drivers and etc. Some games can and cannot support it.
Maybe this time will be different and we’ll see GeForce GTX 670s in sufficient quantity to satisfy the folks previously priced out of the ultra-high-end market. If that’s the case, then hell yes. GeForce GTX 670 is a phenomenal little board that blows right past the GeForce GTX 580—a card that was introduced at £400 a year and a half ago. It offers the display connectivity to contend with Eyefinity, one of AMD’s prior differentiators, and its efficiency is currently unmatched. We have every reason to recommend buying a GeForce GTX 670—even as an alternative to the GeForce GTX 680, which is marginally faster, but 25% more expensive.
Basically, it's second fastest GPU in the market, and has insanely high performance for its price.
Well I was about to pull the trigger on the 670, but someone told me that it might be overkill because I won't be gaming at a high resolution. (Have a 21 inch monitor) They said I could save a couple hundred bucks by getting a 560 Ti / 6850 / 6870 / 6950 instead.
It really depends on the games you play. GTX 560 Ti will max all most games, but not all of them. Namely it cannot max out are: Witcher 2, Metro 2033, Crysis 2, Battlefield 3, and similar graphically intense games. GTX 670 however, would max everything today and will continue to do for over 2 years. It's your choice really .