Honestly, I had the Nexus 7, although the 2012 version, and I wouldn't want to go back from my iPad mini.
I believe even the old Nexus had a better screen resolution than the Mini, but I still prefer the iPad Mini screen. It's glossier, and more vivid - it also provides a lot more screen real estate, seeing as it does not have the on-screen-buttons. Moreover, the Mini just works, all the time - with all my devices. My Nexus took forever to charge, and suffered from its shares of problems.
The only two things I miss about the Nexus 7 are the flash-playing abilities and the option to install uTorrent.
The screen isn't super - but it isn't as bad as some people make it sound. But if I were you, I would probably save up some money and get the Retina. If you plan on keeping it for a while, the Retina will be worth it. It's better to wait a month or two and buy the Retina, than buying the normal one now. However, the normal iPad Mini is a better experience than the Nexus 7 IMO (many people will probably disagree, but I've used both extensively now, although not the 2013 model of the Nexus).