Get the Saturn USB re-release from about 2006. They are white with blue buttons (ugly, I know -- they should have kept the black and grey). They have a "Play Sega" sticker in the middle. Do NOT get the "saturn-style" knock-offs.
I got a few new off of eBay for about $6 a piece, they are great for classic / MAME / shmups.
I got a few new off of eBay for about $6 a piece, they are great for classic / MAME / shmups.