ardcp:

Although the Marble Institute of America doesn't recommend the practice, I wouldn't have any fear if a seam were properly supported over a dishwasher. Sink seams are fine too.

That said, a fabricator who seams for yield is saving you the most money, because the material is costing him less.

Remember, you don't get to have it both ways. If you pick a stone with lots of movement that's difficult to seam match, it may require another slab that a less expensive, better yield job without a fussy match would not.

I was in the same situation, we put the seam in the sink, right at the faucet. I did a great job laying out my slabs (if I do say so myself!), so even though I have movement, the seam matches pretty closely. The other placed they suggested was at the corner of my L, which would have been a much longer seam. You can barely see my seam at all with the faucet.

Here us a picture, pardon the mess in the sink. And the lack of backsplash!

I have a seam at my cooktop and one in the corner.
They are both well done and I can barely feel them.
I do have quartz, so you can see differences as it is impossible to totally line up the newer flowing quartz.
I had a sink seam in my "formica" which was not a good idea as water eventually go into the area and I had a raised area. Not sure that either stone or quartz would have that issue.
Corner seam

The best location for a seam is where the experience of your fabricator says is the best location. If you've done your due diligence in picking a fabricator, then trust the fabricator's judgement. If all you shopped around on was price, then you could have any number of issues. How long have they been in business, and what does the work look like that you have viewed? If you can't answer these two vey simple questions, then you have more work ahead of you.

I remember a thread from oldryder where he discussed why a seam at the sink isn't the best place but that some fabricators do it rather than go the extra step to support the cut-out properly when they transport it. Wish we could sticky his threads.

I am a fabricator.

There are often at least a few options for seam locations. Seam locations in homogeneous material (little or no movement) aren't important if the fabricator is skilled since such seams will be hard to spot unless looked for.

There are various opinions on seaming at a sink. We don't do it for the following reasons:

1. The sink would normally be the busiest place in the whole kitchen so why put a seam there. (note if the sink is a drop in then most of the seam would be covered by the flange on the sink and the rails remaining after a drop in cutout might be too thin to allow moving the part without seaming.)

2. The vacuum cup/ratcheting device used to make excellent seams cannot be used to seam the sink rails. This doesn't make it impossible to do a great seam at a sink but it definitely makes it more difficult.

3. Fabricators like seams at the sink because it mostly eliminates the risk of a cracked sink rail which can easily cost the fabricator a couple of thousand dollars. Good for the fabricator but not necessarily the best option for quality.

After 2 years at GW, I have just clipped my first post. Thanks, oldryder!

"2. The vacuum cup/ratcheting device used to make excellent seams cannot be used to seam the sink rails."

It can be used, just not the usual way. Set the vacuum pods on each side of the sink and pull them together with bar clamps attached to the outside of pods. You'll lose the cam function, but that shouldn't be an issue on two 5" long seams properly shimmed.