I stayed at the Kingdom when I was at Vic Falls about three years ago, and based on that stay, my sunset drinkies at the Victoria Falls Hotel, and dinner at the Illala Lodge, I would recommend staying at the Illala Lodge. The Kingdom's most positive aspect is the fact that you are a five-minute walk to the Falls...but at the Illala you are a ten-minute walk to the Falls. No big deal. I thought the Kingdom was cheesy and depressing--although the rooms are quite fine, the Disney-esque grounds and the casino are pretty icky. The Vic Falls Hotel was very lovely, and I'm glad I went there for drinks, but I can only imagine how much they charge for rooms. I booked with a travel agent in SA and still (as an American) paid well over $100/night for the Kingdom.
Meanwhile, the Illala seemed much more pleasant. Certainly the restaurant was nice, and quite lively whereas the Kingdom was depressingly deserted. I think the hotel must have had about 20% occupancy at the time (September 2003).
I too thought the booze cruise was well overrated--we didn't see any wildlife at all, so if that's what you're going for, you may want to save your expectations for the actual safari portion of the trip. What I do HIGHLY recommend was the whitewater rafting (we went with Shearwater Adventures). This is not for everyone, but if you like adrenaline rushes, you will get one with this experience! I had a complete blast!