Edit: just read the sticky, i don't have a graph yet as i haven't tuned and was looking for some advice. If i posted in the wrong area please let me know, and my apologies if that's the case. Thanks!

How and what factors does everybody put into consideration when choosing a shop to bring their car in to get tuned? I'm new and also aware that reputation is probably a large factor in a decision that anybody makes but is there something else? I.E what separates one shop from another, or one tuner from another? Any advice would be much appreciated.