Before Sonic Origins , This was the best way to play Sonic CD. The added features are great, and having the game in widescreen is very good. There are a couple visual and gameplay differences, some positive and some negative.
I'd say this is better than the original Sega CD version, but not Origins Plus as that adds Knuckles, Amy and the Drop-dash into the game.

My usual opinion of Sonic CD stays the same though, still being a game I consider good, but my least favourite classic Sonic game.
Yes, I think this game gets it's dick ridden too much, it's not the best Sonic game.