Hotel: Conrad Abu Dhabi at Etihad Towers
Room Booked: Superior Queen
Rate: US$266 including tax
Early Check-in: Arrived at 9am and the room was ready
Late Checkout: Asked for a 3pm late checkout at checkin, got a "you know you have a 4pm option" which I initially declined. When I was a little late getting back, updated to 3:30pm around 2:30pm and they didn't even blink at honoring it.
Upgrade: To junior suite on floor 56, a 3 tier upgrade, but no Level 45 (club) access.
$100 Food & Beverage Credit: AED $348, about $95. Good on all ten-ish restaurants you can charge food to, but not at the pool bar, gratuities, in room dining, or minibar. Did a lovely solo 3 course meal at Michelin rated Li Beirut with a beer and still had about AED88 left over that I sadly didn't spend. There are several happy hour options throughout the evening depending on the day.
Breakfast: Includes a very good buffet with multiple cooking stations and each hot buffet area is different (Western, Indian, Arabic, East Asian, healthy). Huge amount of bread options (including like 10 types of croissants, all were high quality. Fruit, salad, and meat/cheese areas as well.
Diamond benefits: Complimentary Happy Hour 5-7p which I was 'happy' with. Good table service for drinks, had a solid red-white-rose as well as some call-level alcohol options. Food was fairly nice as well. A special area at breakfast and didn't have to wait in the (shortish) queue as well as had a special order menu (on top of the buffet) with a half dozen items like pulled brisket benedict and egg cocotte with lobster (I particularly enjoyed, even if there wasn't a ton of lobster in it).
Comments:

• Great hotel, service was top notch and everything was very clean and looked after.
• My welcome amenity was expansive (Decent bottle of South African merlot, 4 macarons, chocolate 'postcard', and fresh fruit), but not sure if for FHR, Diamond, or a bit extra due to having both.
• Hotel includes access to the observation deck (35 AED for non-guests) and the location is central to the new/old palaces, marina mall, and the Corniche. Note that you can visit the old palace (now a Mandarin Oriental) to see the lobby areas for free and it is stunning (although also about 4x the price of the Conrad). I was able to walk over in about 10 minutes, so if you're decently mobile and it isn't disgustingly hot out a cab shouldn't be necessary.
• Nice pool and beach area for an afternoon, but there are likely better locations in Abu Dhabi if your main goal is to sit at the pool/beach for a few days
• This hotel should qualify as a Hilton Resort for the Aspire credits. Will update if/when they post for the gratuities I left.