iFi would be better than the Swans with a similar sub in the clarity department. Better driver materials, better bracing, less distortion, better served for near-field performance.
Swans would have over the iFis in dispersion, soundstage, and larger sweet spot, but you would have to position them much farther away than the iFis to get the most out of them-- 1.5 times further apart than you are sitting away from them, and probably a nominal distance of about 5-6 feet toed-in.