I stayed here when visiting a trade show at the Messe. Although it's not as convenient to travel there from here as other places I've stayed (you have to take a tram, then the U-bahn), it is convenient in other ways.
It is a basic accomodation, but very clean and newly refurbed. Good mattress, good quality duvet and pillow. Also the usual satellite tv and pay per view movies. I liked the safe which was big enough for my laptop but it does cost 1 euro a go!
No minibar but this really isn't an issue - they provide a large bottle of fizzy water, there is a supermarket almost next door and in the side streets either side of the block there are some late night stores.
There is no hotel restaurant, but again, this really isn't an issue - either side of the hotel there are some excellent Chinese, Thai and Italian takeaways - one night I had a takeaway in my room. You will need cutlery though as the takeaway I went to didn't provide it.
Breakfast is standard German fodder - meat, cold cuts, cheese, some cooked items, cereals, yoghurt, juice. Perfectly adequate.
Staff were friendly and helpful.
The only downside I can think of is that some rooms (i.e. mine) face the very busy road and there is no aircon meaning you may have to leave the window open and wear earplugs (I came prepared). When I say this road is noisy, I mean REALLY NOISY!
The room was quite hot when I was there (20-22 September) so it could be a bit uncomfortable in the summer.
All in all, good value - would book again.