Mount Rainier is a relatively obscure format for rewritable optical media. In short, it has a system for error correction such that your data on RW discs remains readable for a longer time.
CD+G read/write means, if I recall correctly, that the drive can read and write the sub-channel data on CD's. CD+G is most popularly used for karaoke CD's. The lyrics are stored in the sub-channel.
Regardless, if your main objective here is to play backup Playstation games, look toward Swap Magic 3 and Breaker Pro.
edit: I see the Asus 1814BL/T on Newegg for $42.