The Marriott in St Kitts is your run-of-the-mill, generic tropical island resort. You get the sense that you're a customer rather than a guest because it's so big and there's so many people. This isn't necessarily a bad thing - the hotel itself is enormous, with all the requisite amenities - multiple restaurants, a casino, several large pools, bars, etc.
We had a few issues on check in (we requested an early check in which they had some difficulty accommodating) but we found this was sorted far easily when dealing with Kevis on the front desk as opposed to any other staff. In fact, the service was a bit hit and miss - some people, like Kevis and one waitress at lunch by the pool were fantastic, while others were simply awful.
The rooms themselves are well appointed (A bidet! Now that's something you don't see everyday!) and were kept clean and tidy. No issues with my room at all.
The internet was a bit tedious and expensive but it did work. It was annoying not being able to use it on multiple devices at the same time (if I logged in on my phone my laptop connection would cut out) but it did work and I never encountered any issues with it. Pretty fast too.
Do not bother with the $6 Pina Coladas/Daiquiris at the bar by the lobby, they are made with artificial "mix" out of a giant blender/mixer rather than actual fruit and taste revolting.
Breakfast on Sunday morning was insane - tons of people, big wait to get anything. Show up early if you don't want to wait in line. The freshly made blueberry waffles are amazing through!