dbwithlemon wrote: I've heard the video quality with the RCA setup isn't very good, but don't have any frame of reference for how bad it will be.
This does depend somewhat on which video standard you use (NTSC or PAL). Being from the US, I know NTSC; PAL should *probably* be a smidge better with good hardware.
In general terms, you should get 480i
class performance. With a good video monitor and cable, and assuming the Pi does things properly, you should be able to get decent 640x480, which is enough to display an 80-character, 24 or 25 line terminal window and do real work on the command line. (People certainly managed back in the 80's.)
However, this isn't always the case; there are reasons that back in the day people using PCs plugged into ordinary home TVs frequently only ran 40-character screens, because the usable resolution for things with sharp edges like text was about half the theoretical. (This sort of thing used to be the primary distinction between a "video monitor" and a "television", along with a monitor not necessarily having an over-the-air tuner built in.)
Now, modern TVs are so much better than from decades ago this should be a non-issue. But it turns out that old-school RCA input is so depreciated in some areas that some TVs do a surprisingly bad job of scaling it, since basically no one cared to do better.
Some real world thoughts: Anything a Pi 1 can emulate at full speed (generally, 4th-gen consoles) should look fine, as they were intended for those sorts of TVs in the first place. The Pi 2 is starting to get into PS1 (5th-gen console) emulation territory; games in that era were still designed to be usable on NTSC, but some may not look quite as good as they theoretically can. You will certainly be able to use a 40x12 terminal, and probably a 80x24 one. Using X11 for anything but the simplest tasks will be painful; among other things, many menu screens assume you have at least 800x600 available. The Pi is *usable* down to at least a 3" diagonal, NTSC input, 320x200 car-mount screen, but neither practical to do much serious work nor a lot of fun *as a PC* at those resolutions. (It's awesome as an embedded system still, of course.)