I have 3 Rythmik subs and am a fan, but if Brian was indeed bashing his competitors in that way, it's unfortunate. Speak to your strengths and what differentiates you from your competition, yes. Bash your competition - in my opinion that's un-called for and unbecoming.
I've never owned a Rel, but I've heard them in a couple of nice systems and was impressed. We have a music club that meets at a local audio store and there's usually a smaller (10"? - not sure which model) Rel in the system and it has done a nice job filling out the bottom end in a large showroom paired up with Klipsch La Scalas, Tannoy Canterburys, along with some higher end Paradigm speakers.
We met recently at one of our member's homes and he has one Rel (again, not sure which model) and a JL Audio sub and it was some of the punchiest bass I've heard, very dynamic and lifelike. He has done some pretty extensive room treatment - bass traps in the corners, and diffusion and absorption panels, which I'm sure contributed to the quality of the bass and overall sound.
Not having ever had a chance to compare them in my home, this may be off base, but what the Rels seem to do well is the upper bass frequencies and to be very "tight", "punchy", and "dynamic". I feel like the Rythmik's give you more of the tactile sensation of listening to live music while still being tuneful and musical. I do think the Rythmik subs provide excellent value for the money, which may be in large part due to their internet direct model.
Having said that, SVS has great products at reasonable prices and they seem to be doing well having a mixed distribution model - both internet direct and through dealers. It seems that it is possible to build quality products and build in enough profit margins for dealers to make some money reselling them..