Yes, too many variables to say that friction sway control will always provide more friction than any integrated system. Friction sway controller is a strong clamp for sure, with friction material on both sides of a large surface-area bar. But most integrated systems have smaller friction points at multiple points, at both ends of both bars.
I used to tow a large popup with minivans. Used a 400 lbs rated Single Bar WDH, plus a friction sway controller. Lots of others with similar setups liked the "mini-350" WDH, which had integrated sway control. I never switched, because what I had already worked so well. But when I went to a larger vehicle and camper, and needed to get a new WDH anyway, it only made sense to go straight to something with integrated sway control. Works as a system, takes less time to set up, etc, etc.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller