We stayed at Casa San Bartolome inbetween hiking and exploring the surrounding volcanos with Katchiquel Tours (also excellent).
The location is a ten min walk from the centre if Xela (which gives you some quiet), the rooms are very clean and comfortable. The room also had an adjoining private kitchenette.
The service was fantastic (they did our laundry at the last minute and within 2 hours) and they made us breakfast the night before when we had 6am morning starts. Overall we'd definitely recommend Casa San Bartolome.