We stayed two nights at the Jungle Lodge, which is located right in the park, and you can walk to Tikal and see the ruins. The location was ideal.
The lodge itself is nice, the rooms are decent, the restaurant serves good food, and the lobby is really nice, with a lot of different activities.
They use a generator, so only have power at certain times, and the only place to use wifi is in the lobby. It was not a problem for us, and we welcomed the break from technology. If you want a real jungle/rainforest experience, this is the place to stay.