I stayed here in May 2010 with my sister for a short break to Belgium from the UK. We chose it mostly for the location to the train station and price. Breakfast was good. I cannot really fault the hotel and all the positives other people have said are true, good sized room, clean, friendly staff. The only bad thing I would say was our room was on the main road/square and it was quite noisy if you had the window open. We checked out late on our last day (we stayed for two nights) as it was raining and our train didn't leave until the afternoon. This cost a little bit extra but I don't think it was much, maybe 10 Euros for every hour extra.

We stayed here one night and has three rooms.

Due to a change in the Belgian law it is not allowed to smoke inside public places anymore since July 1st, 2011. Hotel Castel took this event as an opportunity to redecorate the hotel and restaurant completely.

Rooms:
The rooms are spacious and new. A double bed has the matrasses and the sheets apart (so not fighting your partner for the sheets). The bath room is quite big and is clean. As far as we could see, there was only one minus: the absence of AirCon. That is not a problem when the weather is cold, but in case of a hot day it is not very convenient. Sleeping with the window open has two disadvantages: it can be noisy around the station, although that did not bother us much, and musquitos can be a problem.

Hotel:
Across the street of the central station of Gent, with tram stops in front of that station. Tram 1 will take you to the center in about 7 minutes and tickets can be bought easily at ticket machines (EUR 1,20 for one way, 10-trip tickets for EUR 8,00). The hotel/restaurant is specialized in Belgian beers, so if you are a connaisseur of beers than you can certainly be happy here. The female owner can tell you a lot about those beers (I thick there are 2,152 Belgian beers, if I remember her words correctly). The hotel is family run and they are very helpful and friendly. Breakfast was nice, but could use more variety. Parking is quite easy around the hotel, but you can only pay for maximum of half a day (EUR 2.00). On the other side of the station is a parking garage where you can park for EUR 10.00 for one day.

Hotel-Brasserie Castel in Gent is a small, but very, very nice hotel. We were 3 friends staying in a family room, which was excellent. The room has a lot of space for 3-4 adults, it's newly modernized and very comfortable. The elevator is actually riding all the way to the 4th floor.
The hotel is very clean everywhere and the owners, which also are eating breakfast together with the guests, is very nice and attentive to all your needs. The refrigerator in the room broke down and in no time, we got a new and the lady from the hotel even put our beers in the refrigerator so they was cool when we came back.
Parking is a little bit difficult at the moment because of roadworks, but the underground parking lot at the train station is fine. 10 euro's per day is an ok price.
The only recommendation is that aircondition in the room would be very nice. In hot weather, the rooms are hot as well and when opening the windows, some noice from the trams can be a little annoying.
My advice when you are travelling to Ghent: Use this hotel, it has very good value for the money.

The family room we stayed in was ideal having two bedrooms, bathroom and separate toilet and was good value compared to other accommodation I'd looked at. The hotel is close to the train station and trams stop close by so very convenient for transport in to the centre. May be a bit noisy for some if windows were left open but when closed no problems at all. The owners who also own the bar downstairs were friendly and helpful. The bar had a vast choice of Belgian beers at reasonable prices and food was simple but tasty, also other bars and eateries in the immediate vicinity. The hotel is also conveniently close to underground parking at the railway station for 10 euros per day. The walk in to the centre is about 20 mins but as there are two art galleries close by in a park, you could break your journey there, or alternatively get on the cheap efficient trams instead with various ticket options available.