If you really want to play the original Doom and Doom II, then the PC version is the only way to go as far as I'm concerned. It ran smooth as butter full screen back in the day on my 486 DX2-66.
The SNES version was never going to be great. The screen resolution is lower already (256x224 vs. 320x200 on the PC) and even then game play is in a smaller window as opposed to full screen on the SNES. The CPU runs at under 4 MHz. It's impressive they managed to do what they did.
Pretty much the only way I ever played Doom was Death Match vs. another player via modem. I also remember playing some four player matches via a multi-line BBS. Good times.
I think one of the better console versions of Doom was the Nintendo 64 version. It even provided unique levels for that system.
I'd say Doom 64 is an entirely different game. As far as I know no levels are the same.
And I looove the art style of Doom 64, I own it on Steam as well.