Don't buy a Vita just for Neo Geo (buy it for Persona 4 Golden instead). But if you already have a hacked Vita sitting in a drawer, turning it into a portable Neo Geo is a Saturday afternoon project that yields a lifetime of high-score chasing.
If you are looking to play Neo Geo games on a PlayStation Vita, you are looking for .vpk files. The Vita does not natively run Neo Geo games, so you must use Custom Firmware (CFW) and Emulators. neo geo vpk
Some Neo Geo models (specifically early AES consoles and "1-F slot" MVS boards) have a "jailbar" interference pattern on the video output. Don't buy a Vita just for Neo Geo