I've never used a disposable so I'm a biT biased, but I gotta go with electric.
The one I have works pretty well, I can't even feel a thing when I do it so it feels like it's not working, but then I feel my face after and it's all smooth + the hair is gone.
Electrics last a really long time and make the process FAST, like bam done in 2 minutes.
They don't go as deep either which won't work for some, but I prefer it as the hair grows back quicker and I like to rock a scruff.
I think I've used a disposable less than 10x in my life.