...Firstly Sun Beach Club Playa Hotel, Bir El Bey IS closed, however it is joint with Carribbean World which is listed as in Borj Cedria.  I stayed at this hotel for 3 nights 12-15 October 2011 with my Fiance.  I booked this hotel about 6 weeks before stay.  I was looking for an 'AI' hotel reasonabiliy close to Tunis and this seemed to be the only suitable one.  I had read a few reviews before I went which were concerning.  One of which was some else saying that this hotel is in fact closed, after reading this I contacted the company I made the booking with to check this out and they told me the hotel is fully operational and there is just a few rooms which are closed.
This review is really for Club Carribean World the only part of Sun Beach which is open is there swimming pool which is easily accessed and usable from Caribbean World.

-Room
The rooms are chalet / bungalow style (although looking at pictures of Sun Beach it is all in hotels rooms, which I would have preferred hence why I didn't initially book Caribbean World for the fact they have bungalows not rooms in hotel).
The bungalow was fine, it was spacious and clean, double bed, dressing table, TV and nice bathroom.

-Food
The worst!  I am certainly no picky eater.  I would not say the food was 'inedable' but it was not very nice at all.  For instance the milk for cereal at breakfast was sour and warm, they served baked beans, olives and cauliflower as a hot choice for breakfast and made to order omlettes which were cooked in a black burnt frying pan and consisted of nothing.  Lunch and dinner like most AI hotels was pretty much the same, salad - yet this was never replenished, I think it was the most popular dish in this hotel as everything else just looked horrible.  I did try other food, grilled veg - I don't know how they got that wrong but it tasted burnt yet wasn't, the majority of the other dishes were Tunisian speciality which I like to try (only tried once) my fiance is Tunisian and he did not like any of the dishes here.  The pizzas were made to order and they were ok.  The restaurant is plan and simple and you can sit where you like inside or outside (you don't have the same waiter).

-Drinks
Beer, red, white & rose wine, and bouka are the only alcoholic drinks available on AI.  They do sell bottles of Golden Brau and Heiniken I think 2,500 TND  (£1.25) per bottle.  The AI beer is ok.  The white wine was like drinking vinigar (I know you don't get the best of the best in AI but this was below the cheapest wine about (if thats what it was!)
What I disliked is the plastic beakers that you are given for drinking outside.  In other AI hotels I have stayed they have used disposible cups which I think is much more hygenic than reusable plastic beakers with dirty and scratch rims.

-Swimming Pools and Gardens
The swimming pool appeared to be clean and the surrounding areas were tidy.  The entertainment around the main pool was average.  The swimming pool for the Sun Beach Hotel was accessable and usable we just came across it whilst walking the grounds and I recognised it from the pictures when I booked Sun Beach, there were no other guests around it at all.
There are waterslides in the Caribbean World, however...... you have to pay 5 TND pp per day!  Which I don't think it makes sense considering the fact it is a splash resort!  Needless to say there were about 2 or 3 people using them.

-Beach
The beach wasn't looked after at all it was full of seaweed and had not been cleared like most private hotel beaches. It was a little bit slopey but just slightly. It is quite a walk from the hotel approx 400 yards, this did not bother us, but again something to be aware of.

-Entertainment
The entertainment is average, the majority of the hotels in Tunisia use the same entertainment programme so what you are seeing whether how good or bad it is is not necessarily down to the hotel but down to how much effort the animation team make of it.  These were quite a good and friendly bunch. 
There are a few games machines in the hotel and there is a room with 6 pool tables, however each one of them were missing at least one ball.

-Outside the Hotel
I ready a review before I went to this hotel describing the surrounding area as being like 'Bosnia' and some people saying that some taxi's won't even come to the area Borj Cedria / Bir El Bey.  This is not the case I can only assume the guest who made this review had never been to Tunisia (unless they had stayed in Hammamet or PEK which is purpose built).  This is Tunisia there are a lot of barren areas and lots of litter which is what this is like outside it is not unusual.  Re the taxi's the reason that a lot of taxi's don't go into the area is because this hotel is the only hotel here, and if it is off peak then there is obviously not much need for taxi's therefore the drivers are not always going to drop someone off at a hotel is there is not much chance of them picking someone up and making money on their return journey unless they charge you a exceptional amount.
There is nothing outside the hotel in means of shops or anything at all really, I was already aware of the location as we just used this as it was a 40 mins train ride from Tunis Centre. The train station would be a good 25 min walk away, we did use a taxi as my Fiance new how to get hold of one whicih parks up outside train station.
I think there were only another 2 families that were English staying in the hotel. It was mainly Polish, Russian, German and French. One more thing, they do not have a night club in the hotel so in the main show bar they play music for the adults from 2300-0200 which is rather noisey if you are staying in a room near the main hotel which we were.
All in all the hotel was not aweful although the food was.  I personally wouldn't stay here again, but if you have already booked this hotel then enjoy it but just beware about the food (it is cooked properly just tastes aweful).