If you're talking about getting an IPS monitor for the same money as three TN monitors? IPS monitors are used in situations where color accuracy is more important. So, in a production house for magazines, or landscape design, or video game production you would get an IPS monitor. Another reason the monitor works for these situations is because it has a higher viewing angle, so collaboration doesn't mean someone has to give up their seat and a larger group can see the same monitor. For gaming an IPS monitor is actually a waste of money, although there are affordable IPS monitors they are not very good and usually will have slower response times. That does not mean that you will see ghosting, which if memory serves occurs somewhere around 15-25ms in measured response time. In Aces High what response time is measuring is not really so important, until you get over a measure where your eye can see the transition of a moving object forcing a severe color change. So in the case of looking from the shadow side of an airplane crossing a well lit sky you might see ghosting at something above 12ms, but your brain will generally pass it off as something similar to motion blur. Once the response time increases to something like 20-25ms then a rapidly moving aircraft will leave a discernible ghost trail even in low contrast situations.
Generally speaking the response time is not a problem, because monitors have evolved beyond the issue. The problem occurs when a manufacturer tries to pass off a high response time as something lower, by adjusting the test. Monitors that have extremely accurate color are not made to be concerned with response time. Those monitors generally are purchased by print houses where color means more than it is does to gamers. Those monitors also tend to cost more than typical gamers spend on their entire system.