I don't believe that there's any significant problem with DSL Depot compared to other online suppliers. I bought a router from them, and I know Kitz bought two, and their delivery service was immaculate, with complete traceability at all times. Their address is no secret, it's printed on their invoices. They are associates of DSL Source, DSL Depot being the part of the company which disposes of discontinued models, refurbished equipment, etc. They are trading names for:
Net Lynk Ltd.
Roman Park
Roman Way
Coleshill
Birmingham
B46 1HG
A couple of moans on ADSLGuide doesn't mean anything - you'll find similar moans about just about any online supplier.