What position will you be mounting your surrounds in.....To the sides of the seating position? On the rear wall?
This answer would help narrow down your choices, as the Paradigm ADP-190's are very picky as to mounting position. They love to be on the side walls directly in line with the seating area, but hate the rear wall (from what users have told me).
I just got done with almost a week of surround speaker research between the Paradigm ADP-190's and the Axiom Audio QS8's.
If you aren't afraid to raise your budget a little more....can I suggest the Axiom Audio QS8's, at least to test out? They offer a 30-day in home trial, where you can return them for a full refund at anytime. They also have rave reviews all over the Internet.
My LCR speakers are all Paradigms, so I obviously had to make a tough call choosing the QS8's over the ADP-190's, but with the in-home trial, there is nothing to lose. If I don't like them I will know to settle on the ADP's....but if I do like them, well than I keep them
Also, be sure to realize the difference between bipole and dipole speakers. The Swan and Paradigm speakers you listed are dipole, while the Def Tech and Axiom speaker are bipole. Hence why, at least for the Paradigm ADP's, position is key because the dipole design is less forgiving to room layout.....whereas with the Axioms I ordered (which are bipole) are said to be very forgiving to room layout and position.