Are the ac blade razors (DX, SS, etc) better than a slant?
Not in my opinion. They're different, not better or worse.
One reason I think I see is that if you're using a slant (or any T-shaped safety razor) then you are applying motive force to the edge from above and out front of the edge. Pulling it in other words, and the pull can help the razor maintain a light touch.
With a barber razor you are applying motive force to the edge from above and behind the edge. PUSHING it, in other words. While the result in both cases is edge contact with the skin, they shave differently.
Another factor is bar or comb on a safety razor, which is in front of the edge whereas the SS bump is behind the edge. If you've got a light touch anyway you'll have a super light touch with a naked edge -- for self-preservation if nothing else.
A normal head shave with a fairly efficient slant razor (Wunderbar, Stealth, ATT S2, or Fasan Double Slant) takes me 35-40 minutes because I'm an old hippie and just groove on the total experience. The same shave with a naked edge can take 75 minutes. Different tech, different techniques, different razors.
O.H.