My company usually has us ride the train back to Frankfurt the night before our flights home to the US, and we always stay here. All you have to do is ride the escalator up from the Frankfurt Flughafen train station and you are at the hotel. Then your bags are safe if you want to go into the city at all. The next morning, you wake up and walk to your gate! (You may need to take a shuttle between the terminals, depending on your flight.)
After travelling in Europe I appreciate the little comforts like having a washcloth in the bathroom and - of course - air conditioning! And I find the beds very comfortable. Shockingly, I never hear the planes or trains outside, either.