I dont do that much graphic design as much as i do gaming and programming.
I dont know if tn panel color reproduction is not that bad because i can get fast response times with not as good color reproduction or 6ms response time GTG which i dont know if it is too bad.
What do you code in? And forget all that 6ms GTG stuff - manufacturer-quoted specs are a load of crap. What you really want is to actually see the monitor performing in person, or check out professional reviews with high-speed photography, e.g.
You'll find some excellent reviews on there that will give an idea of responsiveness, colour quality, everything you could possibly want to know. Short answer though - trails are really not a serious problem at all with IPS and the colour quality is genuinely superior. Viewing angles on TN are terrible (and I don't mean horizontal for people either side of you, I mean vertical - your own top-to-bottom view of the screen) with serious colour shift / loss of fine detail.