I've never owned a 303 or 404 (been trying to cop one recently) but even with the screen I still barely even look at the waveform much when I edit, I do it by ear. I'm by no means a pro, so the waveform usually doesnt mean much to me.

From what I've heard and read about the sound both the 303 and 404 produce and the build quality, I wish the 303 was portable like the 404. Plus the 303 just has that vintage look to it, which is dope-as-all-hell.