Dells are a whole 'nuther animal. I have a set on my bench right now I'm rebuilding. They should get completed this morning and shipped out today. They have a LOT of parts to remove, clean and put back. They have a LOT of passages to clean. The idle circuits have plugs to remove so you can clean the whole thing. I swear they're equipped with THREE times the amount of brass plugs and screws, brass weights and check balls etc. They have a LOT more O-rings(I count them later when I re-assemble).
Webers are simpler to rebuild for a regular guy. I wouldn't attempt to rebuild Dells unless I had more experience than most. It's been a while since I've done a set, I forgot just how many pieces they have. Webers have two O-rings for each circuit, one for the idle jet holder and one to seal the mixture volume screw. That's it. Carb top gasket and float valve, and some aluminum crush washers on the fuel inlet and float valve. No check balls(other than the one inside the accel pump valve).
My point is that to clean Dells you really need to remove them to the bench. Blackline/whoever totally deserves the money they get for a rebuild. Webers can be cleaned really well ON the car, only removing the carb top and idle circuit stuff.
Dells are great carbs, but complicated to do them RIGHT. Webers are certainly easier to maintain IMHO.