We stayed for 4 nights at Hotel Kaiserhof in Offenbach just outside of Frankfurt. Although outside of frankfurt it's an excellently placed hotel - just two minutes walk from the train station and a few minutes from the main Marketplaz of Offenback (though to be honest I'd make the effort and hop on the train to Frankfurt). There's even a great internet cafe a few doors down as well as a museum ten minutes walk away.
The hotel itself is very reasonably priced and although it's not in the most picturesque area we felt very safe walking into the centre quite late at night. The rooms are definately above average for the price that you pay and very clean. The staff were incredibly welcoming and helpful throughout our whole stay.
I would definately recommend hotel Kaiserhof to anyone who is looking for an above average reasonably priced hotel within a short distance of Frankfurt.
