I just got an AOC i2267fw this week. They may not have the most robust design on the market, but the display is aesthetically pleasing and comes with a very good IPS panel at an affordable price.
I mirror displays during lectures from time to time, but have never given a whole lot of thought to the display resolutions, but I'm usually using a projector, and the room I was in this semester had an awful projector.
After a few minutes of tinkering this morning, here is what I found. Using Display Menu, a little app that brings back the menu bar item for displays preferences as well as a few other functions, you can choose the resolution you want to mirror. With mirroring turned on, the default is to have the MBP display at 1280x800 and the external display at 1440x900. Things naturally look great on the MBP, but not so great on the external. It allowed me to switch the external display to its native 1920x1080 resolution and showed a scaled 1920x1080 on the MBP, with proper aspect ratio, so the MBP had a black bar across the bottom. Naturally, in this configuration, things don't look great on the MBP.
I suppose it boils down to what you need to accomplish. Do you need to have both displays looking great, or just the external? For a quick presentation, Display Menu gives you the tools you need, but if you need to work in mirrored mode for an extended period of time, then it might not work out the best without a retina display in the MBP.
If you can give a few more details of what you need to accomplish, I can test a few things out for you and report back.