TLC Tree Expert, Inc

After talking with friends about the mature ash tree in our front yard, we knew we wanted to have the pruning performed by a certified arborist to ensure that the tree would last for many years.  We received quotes from 4 different companies and chose TLC based on Chris's knowledge, professionalism, and the price for the job.  TLC was on the higher end of the estimates (we rejected the lowest bid since it was way too low), but Chris was negotiable on price -- we felt we got our money's worth for a job well done.
We had to reschedule our initial appointment due to weather, but Chris and his team (2 other certified aborists) showed up on time and got right to work trimming our trees.  It was amazing to watch those guys up in the tree pruning out all the dead branches and just generally shaping up the tree.  When the work was finished, we were really pleased with the final product -- our tree retained a nice canopy and will be safe from snow damage this winter.  I'm really looking forward to seeing the leaves return in the spring.
The pine in our yard also needed some trimming and had some old moth damage in the crown.  They trimmed this up as best they could (it's planted too close to the ash and is growing diagonally), and Chris had some good advice on how to plan our landscaping as the tree ages.  This tree will need to be removed in the coming years (too close to the ash tree, dead branches), but TLC did a great job making it look better considering its condition.
Overall, a great experience -- I'll go back to TLC when it's time to have that pine taken care of. 
A general word of advice: if your tree service needs are time-sensitive, make sure that you're booking an appointment at least 3-5 weeks before you need the work done.  I think it was partially due to the time of year (people wanting to protect from snow damage) and that the good arborists are really busy, but that seemed pretty consistent across multiple providers.

It went very smoothly.  The owner was involved. They knew what they were doing and very efficient.  They lifted the tree over the top of my house.  He did everything that I asked him to do.