cannot said since my ips monitor is dell u2312 model that have very good input lag, not as low as TN but I'm cannot see any ghosting..(this can vary to each person)
All TN panel like the asus will go dark/bright if u watch it from a above/bottom/sideway the color is also turn kinda yellowish this is annoying for me since the monitor center is not level with my eyes...
IPS have none of this problems and the color is vivid/lively (u need to see yourself, it much better than TN ones), the bad is at dark movies black is looks like dark grey... but since i watch bright movies more this not a problem for me...
for contrast ratio... just ignore the number, it was listed dynamic contras number the real contrast number about 500 ~1000 range.. but as stated the IPS has weakest in reproducing Deep Black.. the contrast is not as high as TN...
But all that for me, I'm favoring IPS panel since i like to see how good the color and i don't need to stand still when watching movies...
I'm also not playing fps a lot...
so for your question :
1 - is it awful for fps? depends on the monitor build some are not noticeable some are very bad... I haven't read the review for this specific lg model
2 - viewing angle is it bad ? yeah if it not level with your eyes, but this TN panel characteristic.. IPS strong point here
3 - what recommend ? I have tendency for IPS but I can only speak for myself...
4 - contrast number ? just ignore the number.. TN are better in contrast, IPS deep black will look like dark grey...
hope this help...