I use a Merkur safety razor, but most often I use a commercial shaving cream like Gillette as I don’t have the time it takes to break out my brush etc.
I look at it as I get the benefit of cheap, close shaves, without the longer process of using my brush to lather up. Maybe if I had a nice badger brush I’d feel differently.
As for the blades - Astra are a good general purpose blade I like. Feathers, as someone else mentioned, are wicked sharp, and require extra care.
Moving from cartridge expect to take some time to get the technique down. You can’t go as fast.