sorry to jump on the thread, but same question as OP, for photo editing purposes.
U2713H - looks good. Currently using 2 27" shimians..how will they compare? I do not remember the specs on the shimians, bought more than 2 years ago.
Also, how would the U2713H stack up against 4k monitors coming up? It's on my radar now, even though no real need to upgrade monitors, but new house coming - might as well consider.
If you are serious about photo editing and wanted good colour reproduction, you need a monitor that can produce the gamut of colours required for your works. Having the highest resolution monitor will not get you good colours. If the monitor can't natively produce the colours required, no amount of calibration will make it better.
4K monitors are definitely good, but you also need to have really good graphic cards to drive that amount of resolution. U2713H is a really fantastic make with a reasonable pricing. Read the review here if you want an in-depth analysis of the monitor
Dell U2713H Review
I realise for Dell 4K monitors, they are using TN panels, hence ain't suitable for good photo editing works today. ASUS PA328Q is a 4K monitor at a rumoured price tag of USD3.8K. If you feel your work is so important, you might wanna consider it ?
Just a work of advice, having the best colour reproducing monitor is just one of the colour workflow to get good colour reproduction. You have to remember your audience are not likely to have fantastic monitor themselves to view your works, so take all these with a pinch of salt. Not unless your works are to be printed for display, then monitor is just tip of the iceberg. You will need to also calibrate your printer, and we are talking about really good quality production level printing.