I recently booked a trip through Panama Travel Unlimited and had a really great experience. I emailed many times with Olga and many other people at their office and everyone was a big help. I was a little bit nervous because everything seemed very laid back and nothing seemed set in stone even right up until our trip. We booked a trip to San Blas and there was a lot of variables that seemed like they would just not fall into place but I was extremely impressed with how smooth the whole trip was. My only complaint was that our driver Miguel was a little late and then decided to make 3 or 4 stops along the way to run personal errands instead of getting us to San Blas.
The prices seem too good to be true but they aren't. We stayed at Kuanidup and they were all very friendly and definitely fed us well. They didn't speak any English but there were guests that could help us in that department and they were patient if you didn't understand.
We also used Panama Travel Unlimited for our airport shuttle. It was slightly more expensive than taking a cab after a little bargaining but if you don't speak spanish and are uncomfortable getting a cab right when you arrive I would definitely recommend the shuttle because it was very easy after a long trip to Panama.
Lastly, we did stay at Hostel Mamallena and had a great experience there also. I had no complaints about the hostel and everyone was very friendly.
Overall, everything was perfect and I would recommend them to anyone looking for a great travel experience.