Here is my review of the differences between the services provided by Seattle based  International Mountain Guides (IMG) and those provided by Nepal based Asian Trekking (AT) for climbing Mount Everest from the Nepal side. 

For the benefit of people looking at this page who didn’t follow my dispatches throughout the expeditions, I attempted to climb Mount Everest in 2006 however when I was 100m from the summit, my oxygen bottle ran out and I turned around.  I went back again in April 2007 and reached the summit on 23 May 2007.   On my first attempt I used IMG to organize all the required Everest logistics (they market this as their non guided program).  I was unhappy with some aspects of IMG's program (some details below) so in 2007 I decided to try a different company.  There are many alternatives available on the market, and after reviewing almost all of them, including the guided Everest programs, I settled on Asian Trekking's logistics package.  The following is a comparison between the two based on my experience. Although I haven't explicitly spelled out the criteria I used to evaluate the different providers, I am think that all the factors that were important to me have been mentioned here, so this may be of use to people evaluating different climbing companies, even if you are not considering Asian Trekking or International Mountain Guides.

Food
All food for the duration of the expedition was provided by both companies, with cooks stationed at base camp and camp 2.  I was reasonably happy with the food provided by IMG in 2006, however after going back a second time and comparing the two, I believe we received much better food through Asian Trekking.  Of particular note was the fresh fruit Asian Trekking supplied for most lunches and the amount of protein we received.  You can read more about my experiences with food on Mount Everest here.

Leadership
We had quite different leaders on both expeditions.  The leader from IMG was very organized and experienced however he tended to run the expedition in an almost militaristic manner.  I found that Asian Trekking’s leader suited me better as he was more approachable and consultative.  This might not be best for everyone, but here are my comments.

Sherpas and other local staff
The Sherpas are critical to the success of most expeditions on Everest.  Both Sherpas were good, however I found that the Sherpas from Asian Trekking were more eager to help.  A particular event made me feel very uncomfortable at the end of our expedition in 2006 and was a significant factor in me choosing a different company for 2007.  See my full discussion here.

Communications
IMG had better radios than Asian Trekking.  Battery charging facilities were both good.  You can read more here.

Gear and camps
Asian Trekking provided more tents and better quality than IMG did in 2006, although I did notice that IMG has new Coleman tents at some of the higher camps this year.  Camp placement was good on both counts.  Read the full review here.

Price and payment terms
Cost is similar between the two companies, with Asian Trekking just slightly cheaper.  I was much happier with the payment terms offered by Asian Trekking than IMG as we could pay a $2000 deposit to secure our place and then make our final payment right before departure to Nepal.  Here's what I paid and when.

Oxygen
The oxygen system used on Everest is a big difference between IMG and all other expeditions.  There is no one perfect system, although I do reckon that Poisk is better than the system used by IMG and is the reason why almost everyone on the mountain uses Poisk.  Oxygen was a major reason why I chose a different company in 2007.  Here is some of the research I have conducted on the topic.

Medical support
IMG paid for each of us to be able to access the base camp medical facility whenever we wanted.  This wasn’t provided by AT, but I have been told you can arrange this same level of cover with them directly for yourself for less than $100 for the duration of the expedition.  You can also pay per consultation - I believe it's $50 per visit but I didn’t need to visit the medical clinic this year.

Dates
With Asian Trekking we arrived at Everest base camp in 2007 on April 12, 8 days later than we did with IMG in 2006.  I think that arriving later was better - in fact we could have even arrived a few days later.

Trek in & out of Everest base camp
In 2007 we stayed in lodges and in 2006 we camped while trekking into Everest Base Camp.  Having done both, my preference is lodges.  With a room inside a lodge you are out of the elements, can stand upright, move around and spread things out in your room, and who wants to spend more time in a tent when you are about to spend two months living in one.  I had people accompany me on both my treks into base camp and there is a big difference between the prices charged for a trek and also the service offered.  See discussion for more details.

The other team members
In both years we had great team members, although I think that we felt more like a team in 2007 than in 2006.  Was this just me, luck of the draw or was it because of having 8 members instead of 16 last year?  See comments about Asian Trekking providing separate camps so that we had a smaller team size.

Anything else
I think it's important to add that in my opinion AT runs a cheaper operation on North side of Everest, so I wouldn’t think that what we experienced this year on the South would necessarily apply to the North side.  The price reflects this, and it's not all made up of the permit difference.  One of our team members this year had used AT on the North in 2006 and he said that the food in particular was much better on the South this year.  This stands to reason, because it would be much more difficult for a Nepalese company to supply a team in Tibet than one in Nepal.  Having never climbed on the North, I have no first-hand experience with this and so can't comment.

I did look at about 6 other Nepalese companies when deciding on an outfitter for 2007, but I found that while there were many that could organise an expedition for a small group, no one else had a package designed for individuals who wanted to join a team.  Some would even organise an expedition for one person, but I didn't want to be on my own for this amount of time.  I also felt that extras such as heater in the base camp dining tent would be left out in a one person expedition.

There were two things that really swayed me in my choice of Asian Trekking for my second expedition.  I received a number of very positive recommendations from climbers that I knew first hand.  Secondly, I looked at the number of people making repeat attempts with Asian Trekking and thought that this counted for a lot.  Some people were onto their third attempt and had used Asian Trekking each time.  If they weren't happy then they would have chosen someone else.  The same goes for me - if I was climbing Everest again from the Nepal side, I would definitely use Asian Trekking.