Undermount is definitely the way to go, as it allows easier cleanup of the countertops by just sweeping water or debris into the sink. Personally, I prefer the look of an enamel sink. I had a stainless and switched to white. I find the nice bright white warm look preferable to the cold look of stainless. I also find it easier to see things I'm working on, like peeling vegs, against the white background. It's also quieter than the stainless it replaced, but the stainless was a cheaper one, better/heavier ones are likely quieter too. But all that is personal preference, either can be good choices.
I'd also go with a deeper bowl. That gives you more room and cuts way down on splashback when you are washing things. As far as bowl type, I like the 2 bowl type which are split about 2/3, 1/3. That gives you one large bowl and one bowl that while smaller, is still fine for a backup sink. IMO, the most useless sinks are the 2 bowl ones that have one big bowl and one small/narrow bowl. That bowls is actually intended for a disposal bowl, with the disposal going under it. However, I much prefer having the disposal under the main bowl, because that's where I do veg prep and can just send the remains down the disposal. So, in my use, the little bowl just took up space.
Check out the Kohler Executive Chef and the Marsala, which are 2 bowls,
2/3, 1/3, and deep. I went with the Marsala, which has a single faucet hole back of the middle divider and another hole in the corner. That leaves the area at the back rear of the bowls, which normally would be taken up by faucets free, so they make the bowls go back another 3 inchs or so. That's the style I like best.