Is it worth getting a 4k monitor for a late-2012 13" MacBook Pro with Retina display? I know my 13" 2012 MacBook Pro with Retina display won't support 4k (because it uses the Intel HD4000 for graphics), but I need a new monitor.

I just want a monitor that will look good at 2560x1440 (or 2560x1600?) ideally similar performance to the current thunderbolt display.

Will a 4k display (eg. the PB287Q) perform just as well as a 2560x1440 display (eg. the PB278Q) with my MacBook Pro? If so, I may as well get one so that I'm 4k ready whenever I upgrade the macbook.

Update, Details about my usage: I don't care about gaming, I just want something for programming and internet. I intend to just drive this external screen only and leave the MacBook closed. I occasionally dip into Lightroom for photo editing, so image quality is a bonus. It wouldn't be the end of the world if I had to review images on the laptop screen though.
What's officially "supported" and what's possible don't match. I managed to get 4K out of it at 30Hz.

I took a screenshot as proof: 

Just a normal mini-displayport&lt;->displayport cable was used.

More details in my answer here: https://apple.stackexchange.com/a/147765/39878

or on this blog post: http://www.mattburns.co.uk/blog/2014/09/30/running-the-4k-aoc-u2868pqu-and-intel-hd4000-graphics/

2560x1440 works ok but because it isn't HiDPI it still feels like a step backwards. I flip between running 1080p (HiDPI) and full 4k (with the text being tiny).