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.