Count me among the others who urge you to make the decision based on what you really want in your space. I have both. In my home I have a granite island that has nothing breaking it up - no prep sink, cooktop, etc. In addition to using it for prep, it seats 4 and we eat 80% of our meals on it. It suits the kitchen and I love it. In our lakehouse I have a long island with a raised countertop (also soapstone). In that house, where we entertain a lot of overnight guests, I would not want the island to be a single level. When people come down for breakfast, for instance, they can sit at the island with their coffee or juice and chat with me while I prepare breakfast. The spaces are clearly defined, and I don't feel like they're right in my space while I'm cracking eggs and rolling out scones, etc. A tip I got here was to make sure the raised counter had ample enough width to comfortably fit a placemat & dish setting. Having the counter raised enhances the view from the 3-bay window and many casual meals are enjoyed sitting at the island watching the sun rise over the mountains. I would never want to change it out for a single counter-height island. I could offer many examples of why one style works better than the other in each of the houses, but they are subjective and have a lot to do with the flow of each place. That's why my best recommendation is to go with your gut - what you want, and how you'll use it.

A good friend of ours has done many concrete countertops and they look amazing. We seriously considered it for our remodel. The staining/etching is what turned us off. To be perfectly frank I'm a slob in the kitchen. A countertop that would be damaged by red wine or lemon left on it overnight is just not feasible. Instead we went with soapstone. If it can hold up to legions of teenage chemistry students I feel it can hold up to me. :D If you do decide to go with concrete have you seen the books by Fu-Tung Cheng? They're excellent. Soapstone can be a lot more affordable as a DIY project. The quarry we bought from has DIY kits for about $25/sq ft or you could make it even cheaper by using tiles. Soapstone seams incredibly well.

Fwiw, I just mixed faux-marble quartz (Lagoon) with a Carrera backsplash and at least in it's pre-grouted state, I'm really happy. It was hard for me to find a backsplash that worked well with the grey-ish tones of the Lagoon, mostly because my cabinets are painted taupe. Anything that "matched" the cabinets seemed too brownish for the counters. The Carrera blends the two perfectly. I think it also works because I wound up using a very small-scale herringbone pattern, so the patterns in the marble tiles are less pronounced. Fwiw, I don't see the calacutta tiles that the OP posted working with a greyish quartz that's similar to Lagoon, and I'd also be concerned about pattern overload with a subway tile. But having worried about the fake-next-to-real problem, I wanted to at least add my experience that it can be done. One of the prettiest kitchens on here, done by a pro, is GW user @kompy, who used a different marble subway with Lagoon counters, and it looks stunning.

Benjesbride, good idea to message Joe. I'll do that once I'm done responding to everyone. Interesting proposed plan. He's had galley kitchens before and I tried to come up with one with everything he wanted in the galley but it never occurred to me to try a partial galley kitchen (blasted fuzzy brain). Thanks! One hiccup is that he'd have to build a false wall to house the plumbing lines to re-route them to the peninsula. He does not want to request to open the chase to re-route the lines inside the wall. He said it's a major PITA and likely won't be approved (he's remodeled several kitchens in the various condos he's lived in over the years). Anyhoo, adding a false wall is doable but it does reduce the length a bit. I guessed that a 5" thick wall might be enough but his contractor will be able to tell him if that's sufficient. Maybe he can get by with less. He absolutely will not go for a 24" fridge but he might consider a 27", given the right incentive. He's only ever purchased Subzero so I'm quite sure he'll stick with that brand. Other than seafood, he uses fresh ingredients and very little canned or boxed items for cooking so enough fridge/freezer space is a higher priority for him than pantry storage. I tweaked your plan, adjusting it to meet his requested goals. I realized one thing I forgot was to allow for a thicker wall behind the DW and sink cab to house the plumbing lines. That eats into the seating overhang, unfortunately. I kept the aisle at 42" but it could shrink down to 39". Tight for when he's giving cooking lessons but fine for when it's just him cooking. I eased the pinch on the left end of the dining table. It's still on the tight side, especially when it's set for 6, but it's better than the 18" I had spec'd in Plan A. There aren't any corners, which is nice, but there isn't any counter wider than 32 1/4" (to right of cook top). He's used to having nearly 60" of counter on the peninsula. That currently is eaten up by counter stuff (toaster, MW, coffee maker, blender, etc), nearly all of which will go into cabinets after the remodel. The only thing he intends to keep out is the toaster. Anyhoo, while technically he has nearly 60" of prep space, he has less than that in actuality. So perhaps 32 1/4" of prep room will be enough. It also has less base and upper storage. It might be enough but I won't know that until we go back up to weigh each plans pros and cons against his needs. Anyhoo, I'll present this as another option and let him decide. Thank you!