Never had to return anything but both Lendmeurears and Bigbargainonline are legit, trustworthy sellers. Just got my VSD1 from Lendmeurears quick and w/o issue. BBO got me my ST6 MK-II amp and was very helpful and honest. He only had one sample on hand w/o all the accs. and he got a new full pack from the supplier including the cell phone converter jack, the latest NA adapter they were putting in, silicone dots sheet and all. Not bad since he only had the original ST6 listing and not the MK-II and the adapters weren't ready so he had to go through some trouble/effort for me.
I might recommend the VSD1. Those who had both say the VSD1 is better between the GR06 and VSD. VSD1S is coming soon so you have a choice of signature and a good price.
You can read the 200+ IEM review thread for one person's review and scoring of both the AM800 and the GR06. They do sound different. The VSD1 would be more like the AM800 signature than the GR06. I think the VSD1 will sound the best of the three but they don't come with the widest selection of tips(but you can always get those on Amazon.uk).