We stayed here for 3 nights over Christmas 2012, I booked through booking.com in a rush as we were worried about availability over the Christmas period. I then read through the reviews on here and was left very confused as there are VERY different views.
The problem seems to be there are 3 hotels/guest-houses in the area with similar/the same name: there is this hotel, a guesthouse called Thavisouk Guesthouse (but I saw a couple of different spellings for this one on signs) and then a third that was called Thavisock which is quite far out of the main town!
I am reviewing the bungalows that are behind the main hotel building (in Thavisouk HOTEL), these were good little bungalows and had a brilliant view of the Nam Song river and the surrounding mountains. Great location - a couple of minutes walk from town and a stones throw from the bridge which takes you over to where the blue lagoon and caves are.
Breakfast was included and was a basic toast, eggs, sausage you get in most places - you did need to be quite prompt to get there before they put all the food away.
Wifi was available in the main building, hot water and tv in our bungalow and friendly staff on reception who booked cheap bus tickets for us.
Read these reviews carefully before making any decisions on this one - they need to sort out the name confusion!

Previously i booked a bungallow by agoda, but unfortunately there's a bad smell from the restaurant (they throw some food on the land and never clean it), i complained to the staf. They tried to clean it, but it didn't help too much. Not all of the staffs can speak english, just one of two of them.
After cameback from blue lagoon, i decided to upgrade my room. So, i move to the hotel. The room is much better even the different of price is just usd 4 - usd 5.
Actually, this place has the best location. You can see the view of Nam Song Bridge and watching daily life of local people while eating some food in the restaurant. Bus and minivan from Viantiane will drop you here. They will have the new building soon and i think it will be more comfort to stay here next time

I decided to tay at this hotel however I got a bungalow (not the main hotel which looks a lot nicer).

The bungalow was terrible, it was dirty and not in the slightest bit comfortable, It could do with a proper clean. The mattress even felt damp, the bathroom was disgusting, the power to the fridge didn't work and the staff were not very helpful.

Definitely wouldn't stay there again and just could not recommend this place compared to other hotels in SE Asia.

I'm sure the main hotel is a lot nicer, it couldn't be worse so my advice is if you are thinking of Thavisouk then avoid the bungalows !!!