The bottom line is any good hotel in East Berlin will be fine. I only stayed at the Marriott once on a business trip and the Marriott is well located in East Berlin. It was fine. The Hilton is well regarded and well located in the heart of East Berlin. My personal preference is across from the Dom (Church) at the Radisson as it was very well priced and extremely well located. The Ritz Carlton is very well located as well. If you choose a hotel in East Berlin, the subway (or taxi) makes it easy to get anywhere. It is staying in West Berlin (especially for such a short stay) that could interfere with your ability to see everything. While there are lovely large and boutique hotels in West Berlin and they are well priced versus East Berlin, you will waste a fair amount of time staying there. That's my only caution. You can use the subway or taxis for dinner reservations. There are loads of great museums and so much to see, I'm sure you will want a return trip. I really enjoyed the Pergamon Museum and to see the highlights Anne recommended would not take too much time. I was disappointed with the Holocost museum compared to the one in Washington, DC. Wish I were joining you!