gtg response time is an oversimplification - if you consider 9 shades of gray (0% aka black, 12.5%, 25%, 37.5%, 50%, 62.5%, 75%, 87.5%, 100% aka white), and ignore the transitions to the same shade of gray, that's still 72 transitions to measure, and they can all be different - see the monitor reviews at X-Bit Labs where they actually measure all 72. The monitor manufacturers generally don't specify how many shades of gray they measured for, or whether the number given is the minimum, median, arithmetic mean, geometric mean, or something else (and that's before you get into the question of whether the measurements took RTC overshoot into account). TFT Central uses a more subjective test, by photographing a moving image on the screen several times, and showing the best-case and worst-case photos. Unfortunately, I can't find a review of the same caliber as those sites for the LG IPS235V-BN.
If there's a local store you can get to that has this model, you might be able to ask someone there to run a demo game, so you can see for yourself how noticeable the ghosting is.