I have a GEM 1912, Schick Type L, PAL Injecto-matic and 2nr Mongoose.
They all give extremely close shaves, there's no question about that. The SE blades are more rigid than DE blades and that defines the characteristics of an SE shave - control is a lot tighter and you don't feel any 'give' whatsoever.
The GEM, Schick and PAL can be whizzed around the face (light / no pressure) making it seem deceptively easy yet they are extremely efficient. A two pass is the equivalent of a good three pass DE shave I would say in my experience.
The Mongoose on the other hand, and certainly with a Feather Super Pro blade, needs the utmost care and respect otherwise it will bite. It arguably gives the closest shave but I find that you really have to concentrate. Although, there are other more forgiving blades out there but I haven't used them yet - on my to-do list though.
I would say it is certainly worth trying an SE to experience their unique characteristics but, in terms of whether they are better than DE, I would call it 'different' rather than better as there are such incredible DE's out there - I am thinking Feather AS-D2, Ikon Deluxe OC, any number of ATTs.
As always YMMV...