Gokyo and Renjo La trek
The reasons I choose Unique Adventure International P.Ltd. Trekking for a trek to Mustang in 2008, and again a few weeks ago (April 2013) for a trek to Gokyo and Renjo La, is primarily because of the company's responses to specific requests I made. When I shopped around on the web to determine who to trek with, Unique provided me with the fastest and most comprehensive replies to all of my questions. They are also very flexible and can tailor trips to whatever the client needs. I also found that, as a Nepalese company, they are cheaper than Western based outfits. If you book through an outfit in the UK, the US or Australia for instance, you will pay 20-30% more for the "benefit" of dealing with someone local. However most Western based outfits will generally subcontract to companies like Unique for local services, so you are paying more than you should for no real reason. Khum Subedi (one of Unique's owners) and his brother Krishna (who answers most emails) speak and write very good English, so communications have never been a problem for me. Even during the trek, the guides are fluent in English, so you don't need Western based guides that add to the cost.
It is also noticeable how well trained the guides and porters selected by Unique are. A good guide/porter will walk either just ahead, or just behind a client, not too close as to get in the way and not to far either. My guide (who happened to be Krishna Subedi) and both my porters (Nima and Pasang) in my last trek followed my pace and provided the right path suggestions when things got tricky (particularly during the descent from Renjo La in freezing cold near whiteout conditions).
Finally, and I can't stress how important this is in Nepal, Unique provide you with Western toilet seats for any kind of trip! I have bad knees and this made a huge difference in comfort. If you choose them be sure to ask for this little extra service, it doesn't cost anything more but makes life much more comfortable!
Contact me if you need any more information.