There is nothing wrong with the use of shims. Caulk it and forget it, please.

If you put new counters on old cabinets, have them add shims and caulk the gap with a color that is close to the cabinets. Or pull the tops, pull the cabinets and install them correctly.

Laminate counters will flex to the cabinets without cracking (within reason). Quartz, stone, solid surface will not.

QSCCRE:

The next time you post to make a point, please make sure your documentation supports your premise. Your illustrations do not; nowhere do they specifically prohibit shimming. If fact, the illustrations make my point that tops must be placed on flat surfaces. Thanks for making it for me.

Anyone who doesn't use shims to install tops hasn't installed many. You could have dead level and flat cabinets and still need shims to compensate for differences in material thicknesses. Go do a few more jobs and get back to us, please. I'm certain you'll agree.

Their job is to set tops, not decide whether or not other's mistakes should be covered by caulk or matching wood trim. Drag that cabinet installer back out on a no-pay call back and I'll bet his tops go in level and flat the next time.

On the bright side, if you don't notice the gaps, the counters look great with the classic oak.

Once you're sure it's installed correctly (I won't step into that one), don't worry too much about the gap except where it can actually be seen by (adult sized) people when standing or from any seating areas.

Tracy Lathrom MIA guildlines is for Natural and not quartz. Different products.

https://assetstools.cosentino.com/api/v1/bynder/doc/0B425745-8BAC-4A87-9D7B54DA7AC39A1D/silestone-installation-manual.pdf?dl=silestone-installation-manual.pdf

Tracy, the cabinets look so pretty! Can you share some info about how you stained them?

QSCRE - Why are there so many references to shims (including listing them in "installation tools") if you aren't supposed to use shims? I am confused.

Tracy, I'd trust Joseph's analysis.

I work with a company that installs granite and quartz every day. The right way to level cabinets is to uninstall the low cabinets and raise them up, shim them, until they're level with the others. To shim the cabinet tops voids most warranties and is sloppy and lazy. You can tell from the photo that they're shimming with little silicone furniture pads you get from Lowes. If I'm going to spend $3k+ on quartz countertops I want to know they're installed correctly.

notapundit yeah someone who know what they are doing

I don't not see any reference to any shims, and the photo definitely show no gaps. Also the current installation manuals all state the surface is to be free from objects etc.

If you doubt the information ring on of the major quartz manufactures like Silestone and ask there technical department that looks after the warranties. That if you used shims would it void the warranty? The answer will be YES!

And stone slabs and quartz tops are always perfectly flat, and the same thickness? Of course the answer is no.

Even a great cabinet install isn't perfect, the cabinets themselves are not perfect. And even if the cabinets aren't level, are countertop installers are suppose to reset cabinets? No, if it's bad enough they should stop and explain what needs to happen for them to install their tops. Even a great counter install isn't perfect.

I've never seen an countertop install that didn't have a shim somewhere. Anyone who says that they install counters with no shims ever, is a telling a story.

Tracy Lathrom yes it would have to be the most lacking installation and fabrication guide we have seen from any quartz manufacturer but best practices do come into play.

https://www.msistone.com/quartz-countertops/quartz-resources-downloads/  is where all the docs are kept