I do like DefTech, and I own a pair of the SM350. Fine speakers, and I have found that these play nice and sound good on a large variety of gear (tubes, SS, chip amps, Lepai, etc).
But, there are some catches with DT!
Don't pay MSRP--there is better out there for the same $, and DT is often found at steep discounts off MSRP.
The specs on the brochures are completely bogus! Marketing at its finest.
I do agree that there is no reason to look at the DT subs though.
I think you will like your DT system. Personally, I would have not gone with the Mythos, those are as much form factor as function.
And, I do agree, at the $15K mark, I would have been looking at Boutique or Internet Direct speakers!