I've stayed at Casa Rustica a few times with the latest stay for a number of months. I have not found a better place to stay for this price range in Antigua. Posada Don Valentino is a close second but it has the same owner.
I stayed in a room with TV, private bath and free wireless. My room was cleaned daily unless I said it wasn't necessary. The best part about this hotel is the common areas. They have a huge kitchen and TV room. The lobby area is large with another wide-screen TV, pool table, hammocks, tables (some in a garden area) and a small bar. There are also a couple computers for internet access if you don't have your own. You can go up and above the lobby via a winding staircase to the balcony where you'll find more tables and hammocks.
I found the staff very friendly and helpful despite my Spanglish :) Darryl (the owner) is American and speaks English and Spanish. The rest of the staff is Guatemalan and can either speak or understand some English. I didn't have a problem communicated with beginner level Spanish.
The hotel can arrange for whatever travel or touristy things you want to do. I booked all my shuttles, etc with the hotel. I think they charge a small fee (dollar or something) for this service but will also act on your behalf if you have a problem (this is Guatemala after all). In addition they have a number of good contacts for private drivers that can be trusted if your needs fall outside the usual.
The hotel can be a little noisy on Fridays and Saturdays due to the surrounding bars. This is going to be the case with all centrally located hotels. All bars close at 1am which for me is not a big deal on Friday or Saturday.

I highly recommend you try this hotel for yourself.

Casa Rustica is just one block from Antigua's Central Park. Rooms vary in size. Some have private bath, some shared. I enjoyed my stay. Management is friendly and helpful. The music from the bar down the street can be loud on weekends, but the hotel has an annex around the corner (Casa Rustica del Parque, with 8 or 10 rooms) that is more quiet and intimate, and a bit less expensive, too.

I booked Casa Rustica for two weeks based on their website and Tripadvisor reviews. Unfortunately I was extremely disappointed.

My room was small, dark and dingy with no hanging space whatsoever. I had to live totally out of my suitcase the whole time I was there. There was a security light shining into the room all night. The room was only serviced on a casual basis, once every three days. I had to wedge the door to the shower room closed. The sheets were thin and grey, although the bed was comfortable enough. Overall, shoddy.

In addition to the noisy weekend disco mentioned on earlier posts, the maids woke me every morning about 5.00am talking loudly and generally banging around. Although they were there all the time, they never seemed to have 10 minutes to service my room.

The attitude of the staff was one of disinterest. There appeared to be no management and the reception staff were sullen and disinterested. When I asked to change my room, although I could see on their computer there were rooms available, they denied it. The friendly owner Darren, mentioned in previous posts was certainly nowhere to be seen. I was informed by a woman in the kitchen that she had bought the hotel, but I do not know if this was true.

As soon as I could find a vacant room I moved to the Aurora, which although more expensive was light years ahead in comfort, space and a friendly and helpful staff.

This was the first hotel I have found since starting to use Tripadvisor which has been a disappointment, and what a disappointment! Not recommended.

Stayed here for about a week and had a great experience. Rooms are very clean, the common areas are nice and most of all the staff was friendly and helpful with recommendations on tours, restaurants etc. Great internet connectivity too - wireless or on the house computers. Right near the park and on one of the best streets in town for restaurant, cafes and bars. Definitely highly recommended.