Have not used their hosting or registration, though I did have them create a few sites for me when they first started trying to provide affiliate product sites for domainers. Some domainers seemed to like epik's products and others seemed to pan them, citing the cost.
I did sell one of my domains for $1.1K in one of their auctions.
For my part, Rob Monster always answered his own phone and always responded promptly via email. I am not doing business with them, but he struck me as an honorable guy, left a good impression. If I had need, I would do business again with him in a heartbeat.