I actually recommend going a different route for now, which is to buy an old PSP (classic should be cheaper than the go, 3000 models are great) and putting a large memory stick duo inside the system that isn't too high capacity. I've had great compatibility with the 8gb Sandisk memory stick duo. I've only had to buy games from PSN that are multiple disk, but there is a way to get those kinds of ROMs to work, and it requires knowing what you're doing. I've had no slowdown at all on the 3000 model, and no issues with loading eboots converted from the bin/cue or image files. At least you'll always know that the PSP will work with the CFW if you don't alter it after you install it, and with owning a Vita, you still have access to the PSN if that's at the latest firmware.
Or, of course, as mentioned, you could just wait for our amazing scene to come out with more compatible eCFW and not updating your system anymore.