Gaming monitors really are good for gaming because they don't go blurry when you move.A lot of people have the perception its all about the refresh rate but it isn't, actually its the motion blur and latency you notice most with a high quality TN gaming monitor. The massive reduction in motion blur is enormously obviously, suddenly you can move and shoot again just like you used to with a CRT. The reduction in latency makes the games feel more in control and when you die you know you were the reason. Combine that with the added motion clarity of higher refresh rates and you can see why they are very popular with gamers.
IPS comparatively is all about colour gamut (the range of colours it can provide). But the main problem with IPS is its very large amount of motion blur. On a good TN monitor you are looking at about 1-2ms for the pixel to switch, on IPS its more like 14-25ms, which is longer than a frame even at 60 fps (16.6ms). That alone adds to the latency perceived but it also means in motion the image is blurry and you are pretty much always looking at the pixels changing rather than having them settle. Only a few IPS monitors have had decent overdrive added to reduce this but its still not competitive with TN yet.
If what you need is 100% sRGB colour gamut or even Adobe colour gamut then you know that already and you'll be buying an IPS, because full 8 bit or 10 bit colour is what they provide. A current gaming TN is 6 bit + FRC, and they tend to run about 80% sRGB which is what games use. So of course there is the obvious problem that 20% of the colours are missing on a TN, which is noticeable. But its only really fair to compare on a static image, because its there where the TN looses out. But the moment you move and the image changes the TN looks better, its got less colours but its clear whereas the IPS isn't. The question you have to ask yourself is really in a game do you mostly look at the same static image or is it constantly changing?