Newegg
50 RMA's over the last three years. All very excellent overall - some cross ships, some RMA Refunds without restocking fee, and a whole lot of RMA Replacements. I order a lot from them for various business and personal purposes, but it is still probably a higher than normal RMA rate. I guess I just have some bad luck with bezel scratches, bad memory, and the occasional bad hard drive/video card.
Googlegear
One was basically a nightmare, the other very good (with an RMA extension time since I sent it out late by mistake). The first one was horrible, they claimed the memory was working fine but I had a whole lot of Memtest86 errors and instability to say otherwise - new memory worked fine, so it wasn't the motherboard.
Micro-Pro
Nearly three weeks before the refund came through. I recently placed a $450 order with them and the order was simply never processed. To this day, it reports waiting for authorization. I have sent 5 customer support emails and left two voice messages (no live person answers) - yet they have failed to contact me once. I started all of the emails and voice messages after over a week of no movement on my order which was for an in stock item. Absolutely horrible service.
Sundial Micro
Had to return a case for a refund. 15% restocking fee and I pay return shipping, but that is expected for a non damaged/defective case. Good service overall.
Neutron Express
Not bad, not spectacular. Two week turnaround, a bit of hesitance issuing RMA.
Axiontech
Average at best concerning RMA - major hesitance and the questioning of my ability to setup and connect a drive properly.
ASUS
Pretty decent, about two week turn around time. I paid shipping, they paid return shipping, motherboard received back worked.
SOYO
Took at least four phone calls and use of the proper wording and contact person to have them issue me an RMA - absolutely frustrating, especially on a $25 item that was no longer needed and unopened.
Jazz Technology
Two Pioneer DVD slot loading drives defective on arrival - due to bad packaging. One even ate a Windows XP CD. RMA wasn't so bad, but not as smooth as Newegg for example.
Crucial
A small mix up concerning the name on the order at the time of the RMA request, but it was solved and Crucial provides quick service.
Klipsch
Absolutely great service from Amy at Klipsch. I was one of the first 300 to purchase a Klipsch Promedia 5.1 setup and after 8 months I was on my second defective set. After some frustration of getting the huge box, unpacking everything, connecting everything, having them go defective, disconnecting everything, and re-packing everything twice - Amy offered a full refund on the speakers.
IBM
I got several Deathstar 75GXP drives and they were all replaced within a reasonable amount of time. But that whole issue will lead me to boycott IBM/Hitachi drives forever.