I've used PixelExit styles for all my forums, and my largest forum was about to reach it's first anniversary so I contacted PixelExit as we had been using Zipped and I loved their previous custom work. I said I wanted my forum bringing up to date from our current style (Zipped), which was great - but becoming outdated.
A few months ago, I asked for a top-bar to be added to Zipped and they did it for no fee. They added it in this style too. A lot of attention was paid to my current forums, it really just feels like it has been brought up to date and is still familiar. Non of my members have given bad feedback, and Russ has said he will fix any bugs that have been found after finishing the style. Whenever I asked for something else adding to the style, it was added with no hesitation or extra fees and my forum really feels memorable now. I also very close to the launch date asked for a dark style and it was done with lots of time to spare, and it looks brilliant.
If you are thinking about getting a custom style, go to PixelExit
TL;DR: Replies were fast and friendly and it was all in all a 10/10 experience. I definitely hope to be going to PixelExit again for custom work.