Just finished 4 nights at the Montage. Cardboard55's review upthread very much captures our experience as well. We had previously stayed at the Ritz Kapalua and the 4S Manele Bay, and this far exceeded both (can't compare to other Hawaii luxury properties) and was on par with our experience at the St. Regis Bora Bora a couple years ago.
We booked the lowest category 1 bedroom through Amex FHR, which gave us breakfast ($60/day credit in Cane & Canoe or in-room dining), a $100 spa credit and the 4th night free. The materials also noted that we received an upgrade, but I'm not really sure that mattered, other than maybe the view. Our room was enormous - we were in a 3 bedroom that had two bedrooms locked up (so 1 bed, 1 1/2 baths for us). Full kitchen with high end appliances, wine fridge, etc. While we didn't use it all that much, it was really nice to be able to buy wine / soft drinks / snacks off property and then enjoy them without hassle in our room / lanai. We made a stop at Walmart near the airport to stock up, but there are plenty of other stops along the way too. Speaking of the lanai, it was huge. It had 2 lounge chairs, a big circular outdoor daybed, a table with four chairs, and another 2 chairs / side table. We were pretty high up with a view out over the pools and to the ocean. Stunning view of the sunset.
The overall facilities in the place are great - the pools are the best I've ever seen in a resort, and are incredibly private. There were a number of cabanas / lounge chairs that were "reserved" and presumably require an upcharge (we didn't bother asking), which I found a bit tacky given how empty the place felt. However, there were always plenty of well located lounge chairs available, no matter when during the day you showed up. There is also a separate infinity pool overlooking Kapalua Bay called the Beach Club, which has a great view and was always pretty empty. The spa / fitness facility was top-notch according to my wife, who got a massage and did yoga a couple of times while I was playing golf.
The beach is public, but Montage has a deal with the beach hut there whereby guests receive complimentary beach chairs / towels. Stand up paddleboards, kayaks, snorkels, etc. cost extra.
We got incredibly lucky with the weather, with no rain and only light to moderate winds. That is a clear downside to the Kapalua area relative to Wailea, but in three trips there, we've never really been impacted by it.
For food, we did breakfast at Cane & Canoe a couple of times, which was good, though expensive. About a mile or so walk up near the Ritz, there is the Honolua Store, which has an espresso bar and a wide selection of breakfast options (as well as groceries, wine, etc.). It was surprisingly affordable given the location, though obviously more expensive than off the resort. We had lunch out by the pool one day, which was quite good (the Kalua pork nachos are fantastic). For dinner, we ate at Cane & Canoe one night, and were a little disappointed - wait staff was only ok and the food was good, not great. Overall, somewhat disappointing given the price point. We also ate at Merriman's (loved it, particularly when compared to C&C), Sansei (disappointing given expectations - more creative license with sushi rolls with a pretty lackluster setting) and Kai Sushi in the Ritz (we love it given the quality of the fish, but it's not for everyone and is expensive for what you get).
To address some of the other random questions / comments: we didn't receive an email from the concierge in advance, but already knew the deal in Kapalua and are the type who makes our own reservations well in advance anyway. You do not have to spend more money on beach chairs, either at the pool or the beach. Plenty of options included complimentary. Yes, they do charge for snorkels and other beach equipment. It's a little tricky for them given that it's a public beach and the "beach hut" is not Montage owned / operated. We have our own snorkels that we always bring with us, so not really an issue for us there, and we didn't mind paying for the stand-up paddleboards (we also weren't paying close to $2200/night). They were in great condition, unlike at the St. Regis Bora Bora where all of them seemed to have at least one hole. While I can't speak to the expense of having them stock up the fridge, we had a couple of bags of groceries in our car that they brought up to the room and put away for us upon arrival.
Overall, it was a wonderful stay, and so long as the price point doesn't creep up too high, the Montage will become one of our go-to vacation spots.