Last monitor I bought was a 27" IPS 1440p and while it's kinda cool, it sucks having to run games at 1440p for the more demanding games. For working it's definitely nice to have the extra screen real estate but I always use 2 screens anyway so it's not a big deal.
If you have just 1 monitor I'm sure the extra resolution gives you more of an advantage.
The tradeoff that now I need better hardware to run my games at 1440p hurts.
So for me personally, having tried 24" 1080p and 27" 1440p, I prefer 1080p because it's more flexible and when gaming I don't feel like there's a big enough difference between 1080 and 1440 most of the time. 1080p was already sharp enough for me really 
Looking back, a 1080p 24" 120hz monitor would probably have been a better choice and that's probably what I'll go for when I need my next monitor.
Of course with that I'll also need above average hardware to get above 60 fps, but at least I have the choice.
There's not really a choice when you're talking about running games at something other than the monitor's native res so I have to run everything at 1440p, but not everything needs 60+ fps.
Likot Mosuskekim, Woodcutter cancels Sleep: Interrupted by Elephant.
