I've done an RMA with Worthington and it went well. I'm not sure if they tested the dimmer or not, but they shipped the replacement before even receiving the defective unit (of course they had my billing info). I wasn't trying to get money back though, I don't know what their policy would be on that, but I'd expect a restocking fee.
Back when the VRC0Pv3 came out several firmware bugs were present. The head of training for Worthington actually put me in touch with Leviton's project manager for the VRC0Pv3, and they actually fixed the issues! Leviton also ran trials using Premise to replicate the exact problem I was having.
Worthington also runs ASIHome, a retail site, so they have a high level of expertise and even offer free training classes. ASIHome isn't a bad site either. I looked at the AO prices for Elk stuff and found I saved hundred's of dollars ($400 or more, forgot the exact amount) just on my Elk system. Even simple stuff on AO seems to have way too much mark-up for me. I was just curious if they are as easy to work with on setting up a wholesale/dealer account. I see a lot of folks recommend them and always wondered if there was some special pricing they offered or something.
FYI: If you are talking about the new two-way Elk RF stuff, I initially had issues enrolling, but I did a firmware update and things seem to work after that. I do recall having to use an actual keypad to enroll them though. I also wasn't very happy about having to move zones around to use them either, but they did eventually work. If you are using the RF sensors and have a highly technical question, Spanky is great and is active here. He helped me by telling me about an RF debug mode that makes the RF keyfobs many times more versatile with a PC based HA program (see this thread: http://cocoontech.com/forums/forum/42-elk-products-inc-elk/).