It depends on how long you spend on the PC. Both gaming chairs and most office chairs were designed for long use. Personally, I didn't find any more comfortable than the other, as it depends on what kind of sitter you are. Gaming chairs aren't very adjustable but are still comfy after a more lengthier time of use. Most office chairs are more adjustable, so you can suit however you'd like to sit (some end up being comfier than gaming chairs). Whatever floats your boat, honestly.
I wouldn't suggest going over the top with gaming chairs if you plan on getting one, I currently use a kind of mid-range one and I don't find it any more comfortable than the expensive ones. Unless you have a neat reason to, I guess.