I used Thompson Treks. They are big, they are highly professional, and they are very expensive. I knew all that going in, and was and remain happy with my choice, but the group was on the large size (I think 6-8 clients is probably optimal). We did all summit, several of us joyously.
I am glad I did the long Lemosho route this time, as I needed all that acclimatization. I would consider, as an alternative, doing Rongai in a smaller group (i.e., the type of trek I understand that Kurt Wedberg organizes).
