Gamespot is dead on, just buy a Genesis.
It's great having all the classics on one disc, but I don't recommend getting this, just get the ones you want on their original carts or on other collections.
There are gameboy ports of some of these games that control and sound better than these. I had a better sounding and controlling version of Sonic on my cell phone a while back, so I do not get why this was even released like this.
To add further insult to the sound department, the music on the main menu screen is perfectly full fidelity audio, that doesn't clip. I'm assuming it was a space issue or a very last minute compilation to cash in.
And make sure you save your RPGs to the main disc, NOT within the game, because apparently that doesn't work. I do wish there was also an option to go back to the main menu at ANY TIME. You have to either restart the Dreamcast or kill yourself/quit the game then await the game's start up screen, then press every button on the DC controller at once to go back to the menu.