It is amazing to me in a society where customer service seems to me at an all time low, that the small community that is hobby rocketry I continue to enjoy great customer service almost universally. A few recently that have truly been a cut above this already exceptional community.
Robert @ Buyrocketmotors.com - Great site, fast turnaround (singular fastest hazmat shipping recieved to date), clear communication and path to provide proof of cert for first time orders, overall easy to work with, and accepts paypal. (I prefer utilizing paypal where available)
Teddy @ onebadhawk.com - Extremely fast and friendly turn around and accepts paypal. My first order is in transit, but I have no doubt, considering the reputable reviews on this forum, I will be impressed with the quality of Teddy's harnesses.
Scott @ lokiresearch.com - Superb snap-ring motor casings and nozzles, unbeatable liner/casting sets, offers a nice range of very usefull research/EX products, and has quickly answered my sometime rather lengthy question with clear concise communication.
Chris @ csrocketry.com - Great selection from multiple vendors of everthing rocketry, offers a wide range of usefull research/EX products, quick turnaround, fast clear communication, and accepts paypal. Chris is the only vendor on this list I have met at a launch, but he saved the day for me twice at AIRFEST last summer. Chris was happy to take a few minutes to help answer my questions even though he was in the middle of setting up first thing Saturday morning. He was also able to accept plastic payment in the field which for me is a huge plus, as I rarely carry more than $100 cash and prefer to keep that in case of emergency on the road.