We went for a short break a few years back, had a great time. Lots of hotels to choose from, we got a very good price on a very posh hotel, arrived well before check in time hoping to be able to leave out bags and were shown straight to our room. We were in what was the West Berlin, if we go again we'd choose to stay in the East side.
Public transport is easy to use and cheap - get a multiday ticket at the airport.
There are plenty of things to do; open top bus tours, site seeing, etc. you won't be bored. Plenty of places to eat as well.
Our favourite activity, and highly recommended, was a walking tour of the city. It was very well planned, taking us to all the key sites and explaining all about the Berlin, the Wall etc. One of the most fascinating bits of the tour was being shown the site of the Bunker where Hitler died, which was a bit hidden away and not particularly publicized so you probably wouldn't find it without a guide.
I'm sure you'll enjoy your trip.