I can't tell you aesthetically which will be better but this is an issue we considered too (not yet reached installation phase but neeeded to know for DESIGN phase).

Our designer pointed out to us that choosing one thickness over another would have design implications. If you think about it, the thicker your countertops are on top of your cabinets, the higher up your appliances will need to sit to be flush with the surface (ie dishwasher, slide in range if you have one). Also, it could change the distance between the lower cabinets and the upper cabinets unless you've already accounted for that. For us that was significant because the designer was ensuring that we were up-to-code in the distance between the range and the upper cabinets. Anyway, I got a little lost in the conversation when we were figuring all this out, but my point is, that it probably will have design implications that you should check up on.

I don't know what phase of construction you're at but for us, it was certainly something we had to decide way ahead of time before our cabinets were even ordered.

We are going with 1.5" which is pretty standard in the US and looks chunky enough for me. Or rather I should clarify that the front finish is 1.5" (approx 3.5cm). The actual thickness of the Caeserstone is the standard 3/4" (approx 2cm). They put an extra 'lip' on the front so that it looks like the piece is thicker than it is if you see what I mean.

I really appreciate your reply. I am going to go with 2cm.

Thanks!