I'm very late but anyways I used carts all my life until recently switching to DE. I still use a hydro 5 sensitive , mach 3 and a Defender for shaving my head. I didn't really switch to DE because of price , I switched after watching several youtube vids on razor burn. The carts do fine for what I use them for .
used a mach 3 for years,dropped canned goo in 05ish and used a brush and williams/wilkinson in blue tub.got better shaves.started de last year and never looked back. i would use a trac 2 or atra if i had to when traveling.i started with those in the early 80s.
In fact I tried a Flex 4, two strokes on my cheeks was enough. I have never been a fan of cheap Bics but I wanted their cart systems to be a success. In fact I have collected most of the hybrids. I will try again...