I have had almost uniformly great service from audio companies- both hardware and software makers. My only contact with Cakewalk was about a decade ago when I got a copy of Sonar LE with an Edirol 101 and I couldn't work how to make the drum patterns create audio. I sent about half a dozen of the stupidest, most braindead  emails ever written to Cakewalk and they patiently and kindly and promptly answered each one. 
 
Occasionally, an order through a webstore has gone awry  (generally with JRR) but a quick email conversation has always got the problem sorted. 
 
It's quite neat in the music world to have a conversation with the person who actually made your VST or whatever. They all seem so passionate and friendly. 

I didn't anticipate that people would chime in with similar story but I'm very glad to see how it turned out. :)

I like this idea for a thread! Here are a few excellent customer service experiences I've had in the past.

Waves: Not only did they reply to my email within a day, but when I was still having trouble they immediately arranged for one of their reps (a super nice guy, by the way) to remotely control my PC and fix the license issue I was having. 

Cakewalk: I accidentally purchased a plugin I already had and they let me switch it to another one of the same price. 

8Dio: Always responds very quickly and has even given me great customer service.

Sonokinetic: I purchased their Hurdy Gurdy this past weekend. I noticed that the drone string wasn't looping smoothly. I contacted them about it. They said that something must have gotten messed up in Kontakt's scripting in a recent update. They were unaware of the issue and thanked me for bringing it to their attention. They said they will fix it a provide a patch to all owners of the library. 

VSTBuzz & AtomHub: VSTBuzz was having a sale on AtomHub's "Old Mandolin". I tried to purchase it but was having trouble with my credit card; it wasn't being accepted at checkout. Because of this I missed the sale. When I contacted VSTBuzz about it they said that unfortunately they couldn't extend the discount since it was AtomHub's product, but he let Mato from AtomHub know about my issue. Mato then contacted me directly and hooked me up big time (let's just say I got an even better deal than was being offered on VSTBuzz). Absolutely fantastic customer service experience from both companies. 

Another kudos to Cakewalk - they were very prompt and helped me sort out things when I had authorization issues with Z3t4 2.
 
Focusrite - top notch service when I contacted them in regards to authorization issues with the Midnight bundle, as well as with a tiny problem registering Bass Station and lastly, fixing a noisy preamp on my audio interface (they were incredibly fast on that one).They've earned a long term customer with me.