I recently spent c. 12k and got a mixed bag. Would I be asking that firm to help me with something? I don't think so, and anyway they did only that one job so would not feel responsible for anything else.
That is very strange. One should think that in a market that is relatively small, word of mouth is such a powerful tool that shops with bad service and work would have a major disadvantage over other shops that perform better.
It is different for airplane makers, avionics companies etc. as there they got you by your balls once you first purchase their gear. Repair shops are plenty, relatively seen.
I can say that in Germany the above theory holds true: a few shops have emerged as the clear leaders with a strong reputation. They do charge more and there might be a waiting list but after terrible experience with others, I learned that in the end it costs you less and it is more satisfying.
For Avionics, this is Avionik Straubing who will go the extra mile. I am sure there are customers with less positive experience (and they do employ some real pricks, one particular comes to my mind) but I regard them very highly. Just last week Wednesday I mailed them a KX-155 radio with a broken display and on Friday morning the same week it was back with me. I did not ask for priority nor did I pay extra. When I had complaints about their work, the reaction has always been "OK, let's see what we can do" whereas the other shops would usually give me the "no, that's how it's supposed to be", "that was not part of the agreement", "someone else must have broken it" BS. And sometimes a "let's just do it" can save you weeks and a lot of Euros over the "according to manufacturer's overhaul instructions blablabla, we can't replace this one screw, we have to send it to the US".
The equivalent in aircraft paint shops is Kronprecht. They are expensive but both people who used them and people that decided to not use them for cost reasons have confirmed to me, worth every Euro.
If there are only crap shops around, why not start one that goes the extra mile? Often in a market with few participants (oligopoly), there is a situation where none of the players starts attacking the others, all are kind of satisfied with the common low standard.
I have had various email comms with Straubing, including asking them to estimate or quote for a job, and I'd say they need to totally overhaul their communications. A little less arrogance (99% less 
) would also help. Some Germans I have spoken to agree so it isn't just a "foreigner" issue.
Some people are not bothered by that sort of thing, especially in the present world where so many people cannot be bothered to string more than 5 words together (and many probably can't), not realising that what they wrote is useless and will just result in more questions, but I am.
Here in the UK, the firm which a lot would say is the most competent, gets its competence from one particular man who I have met lots of times and he is the most clever avionics man I know. He is the only one I know who actually understands the stuff, at both the connection and functional level. And his communication is good. But his firm has a habit of gold plating paperwork, by doing DER packages for drilling a few holes which the rest of the world does IAW AC43-13. I nearly gave them the TCAS job, until they came up with the "extra" at the last minute.
I don't think paint shops are such an issue in the UK. There are several good ones around.
If I am spending money regularly at a shop including annuals I would absolutely expect them to help out. So far my experience with one in the UK has been good in that regard in spite of only really spending 1k so far there. They have offered lots of free advice so far.
Most of the parts behind the screens in the G1000/Perspective system are easily to be replaced by just sliding out the whole unit and getting it replaced by another unit. At the Cirrus dealers they do the same. But I agree with Peter that if something would be wrong with the Perspective system I would most likely not fly on the Cirrus back home.That said, I still have to see what would then go wrong for this to happen with 2 AHRS and 2 ADC's, no vacuum pump to go broke, etc. Same for the Garmin 430. If that would go broke while in a remote location, you would not easily be able to get it repaired and might not feel like flying it home without it.
