i always prefer using a local, independent guide because my tourist dollars stay with the local community. I was lucky enough to find Teshagar ("Tesh") Berihun Asfaw (business name is TrekSimien) to explore the Simiens and had the time of my life. I just returned last week.
The scenery is breathtaking...there is no doubt about that. But Tesh's coordination of the logistics and his thoughtful guiding made the trip. His communication skills are outstanding and his knowledge of the mountains, given that he was born there, was so helpful. Tesh assembled a great team for our small group, which meant that the transportation and food were terrific and I could simply enjoy the trek and the views.
Here's how to learn more about Tesh and TrekSimien if you're interested: treksimien.com or via FB (search on treksimien). You can also reach him via email at firstname.lastname@example.org. He is always very prompt to respond unless he is trekking in the Simiens, which I consider a good excuse. :)
enjoy your trip! it is spectacular.