First off, the mountain is an incredible amazing experience--definitely worth the flight and the $, however--there was a lot of unnecessary hassle with our trip.
We went with Chief's Tours and Adidas on our trek up the Rongai Route. Communication was done via somewhat coherent emails, but everything eventually was ironed out. However, upon arriving, Adidas 'strongly suggested' that we not do the Rongai Route, and we were forced to do an alternate route because of the 'rain and wind'. We trusted him--and there may have been a lot of rain and wind, but it was a bit of a disappointing bait and switch.
Day 1: Adidas' four wheel drive car had been towed, so he showed up 1+ hr late, without calling or giving us a 'heads up' that he was coming late. After a few more hours of running around town finishing errands and preparing for the trek we finally arrived at the trail and were the last to start the trek. I felt like it was a tourist trap, but we were too invested to quit, and we thought everything would smooth out once we started hiking.
As far as the hiking/food/tent etc, went, I don't have many complaints, and Cheif Tours seemed about average compared to the other camps. The guides/chef/porters were generally helpful, friendly, and good.
My hiking buddy got sick, and this is where I wish we had better/more prepared guides. If everything goes smoothly, it's 'ok' to use a cheaper guide, but if you get hurt, or sick, it would have definitely paid off to have a more prepared guide. Adidas had left myself and my buddy with another guide, Romeley--who was an all around good guide. However, when my buddy got sick, they really only had a basic first aid kit, and no real knowledge of what it might be/how to help him. (Headache, fever of 103 etc.) Which isn't entirely their fault, it's hard to provide any kind of 'first aid' at 4000M, but it still was frustrating. It turns out he had Malaria, which is pretty difficult to do anything about anyway, but it definitely ruined our trip.
I continued to the top in a 1 day sprint to the top and back down to meet my buddy who had started his descent. Unfortunately, while heading to the top I left my backpack with my money with the porters (hindsight 20/20). At some point between me leaving my bag with them, and being reunited with it at the end of the day after the summit, 'someone' stole $130 out of my wallet (luckily my passport and Id were left). Probably a bit of my own fault for being stupid, but it happened, and it was a bummer. I don't think it was any of our guides/porters, but I was under the false impression that just because they were part of our group, they would protect our stuff like it was their own. So... regardless of who you go with, keep your wallet and money on yourself--maybe that's self explanatory, but when you're 4 days from civilization and in the backpacking mindset, where your money and ID are is the last things on your mind.
At the very end, Adidas said he would pay for an additional night at our hotel because of our hassle--Great! This probably would have made up for any miscommunications and disappointments and would have motivated me to write a positive review. We had stayed at the nice Bristol Cottages ($70 a night). However, when the bill came Adidas was nowhere to be found and we footed it ourselves--a kind gesture gone wrong.
All in all, it still a beautiful hike, and a wonderful experience. However, my travel buddy who got malaria would probably write a different review.
Moshi and Arusha are also a little bit difficult to just wander through if you're white as you get accosted by salesmen selling tourist crap (more so than anywhere else I've ever traveled). It's off putting, and kinda ruins the enjoyment of just wandering around a new town as your constantly pestered. Also, there are a few places in Arusha where you can get mugged pretty easily, so again, a little difficult if you're looking to wander around a foreign town and check out the markets/local cuisine etc. However, if you just do safari and Trek, you'll be in an SUV with white people, and won't really get the real experience of east Africa, so you should at least try to get out and about.