GO!!! Do it.
TripAdvisor can be good, but it is full of professional reviewers and also professional bores. They will nitpick constantly because they'll be thinking about their next riveting TripAdvisor review...
I'd say pick ATH over Splash Landings because the decor is more tasteful. Unless you're really la di da, a nicely decorated Travelodge room (which is what it essentially is) isn't going to majorly disappoint. It's clean. (Although I would recommend getting drunk because it's the only way the mattresses are tolerable, I discovered that early this year after YEARS of that place practically being my second home. Oh dear.)
The atrium is lovely and so is the bar and restaurant. Prices aren't totally above and beyond what other hotels charge. Nightlife elsewhere is not generally required. Pick a busy-ish night if I were you, start your evening in ATH watching the entertainment if warbling karaoke is your type of thing (sorry), and then when that bar closes, as it does fairly early, head over to Ma Garrita's in Splash Landings. If it's busy, the bar will stay open until last man standing, I've known that to be 4am.
There's music and cocktails and if you've got decent company, you'll have a good night. I always do.
If you've wanted to do this since you were a child, just ignore TripAdvisor and go and make your own mind up. It's expensive, yes, the rooms aren't going to blow you away, fine, but it's the place and the magic and the experience. You'll barely be in the room if it's nightlife you're concerned with. I've had some of the best and most memorable nights of my life in those hotels. Go and make the best of it.