Just throwing my limited experience opinion in here...

I just started using a DE (40s era Gillette Super Speed) after using a straight for about a year and bought a 7 blade sample pack. I was using the DE for touch ups for some areas I'm not great at with my straights. I started with a Kai 5 blade and used one for about 6 touch ups and decided to do a full shave with it...not the best, felt like it was already dull. I recently put a feather yellow in and have four touch ups and 5 full shaves on it. I had read they could be harsh for the first few shaves so I used as little pressure as I could and was quite pleased. I have officially dumped all of my cart razor stuff and haven't touched my electric since. I've still got five blades to try, but so far I'm really pleased with these feathers and will be continuing with the DE for my daily workday shaves (still going to enjoy the straight on the weekend).