my mame cabinet currently has a 19" acer panel in it (my 20" arcade monitor died and I am waiting for parts to fix it) the 19" tft is slightly larger image size than my 20" arcade monitor.
I can say that although the image is pin sharp on the tft and the colours are strong it just doesnt look right. I cant put my finger on whats wrong with it but I would not recommend it for cabinet use. also remember the problems with viewing angle on tft screens (look from too low down and its dark, from too high and it washes out, if you rotated the monitor this would happen as you moved from left to right)
my thoughts... save your money and get yourself a proper arcade monitor and one of ultimarcs arcadevga cards.