So what happens when a "private installer" blows something up? Does it make it your problem?
I always suggest support the independent shops in your area. Talk to others who have used them. find out who's the best at what. Make sure that they have insurance, have a following and can give you what you are looking for.
The small independent shops are typically great installers with small capital. They are hungry to make a name for themselves and sometimes compromise income for themselves.
Look into it. It's a great opportunity for the masses to get terrific work done.

 

There are advantages to using a non-pro and they are: 1- Cost, 2- they should work around your schedule

The disadvantages: 1-they may or may not actually know what they are doing, 2- they are not insured, 3- they may just be repeating the same mistakes

bottom line has shade tree installations with significant Cons BUT if they are good (mitigating 1 and 3 of the Cons) then (and only then) their Pro's are also significant.

I generally do the work myself or I pay a shop as my time is extremely limited