the dell 22" monitor that has a response time of 5ms or the dell 2007wfp monitor that has a response time of 16ms? i don't really know what response times mean and what is better. i'm not a gamer if that matters. thanks.
iirc the dell 20" uses a s-ips (or similar) panel while the 22" uses a tn panel.
20" s-ips has better colour accuracy although slower refresh times (but to be honest I never noticed any ghosting on my 17" with the same type of panel. Same type as used in the apple monitors basically
22" tn has lesser colour accuracy (improving) but faster refresh rates for gaming - not used in apple screens
If I was to pick it would be the 20" or the 2407 24" due to the better panels.