Hiya,
Maybe I can help explain the deal with injectors. Years ago that was my go to razor, and the shaves were close and very comfortable. It also made the switch to a DE really easy, which is a big bonus.
Injectors are a lot like a DE in some ways. Not all of em shave the same, and not all blades perform the same as well. There's gonna be some trial and error finding the right combo if you're looking for the best possible results. Some injectors are aggressive and some aren't, and you gotta try a few to compare em. The earlier models with short handles are gonna have more of a bite than the later versions with a different head design. Each type has their fans.
If there's a weakness in the system, it would be the blades . The currently made ones range anywhere from fair to good, at least to me anyway. There's maybe 5-6 brands here in the US, and some are even sold in drug stores. Probably the better of em are the Schick blades made in China(not the German ones).
Best blades I found were vintage ones and those are what I used all the time. Heh, matter of fact I still have a 72 blade stash of NOS injector blades from the 70s. The Chinese Schick blades are good, but some vintage blades work better for me and some other people as well.
The shave itself is a fair bit different than a DE shave. The injector weighs about nothing, so some pressure is needed over the rough spots. The blade will sometimes need a little help to keep from chattering, and you need to learn that little bit of technique of bearing down.
The injector blade is lots stiffer than a DE, and it feels different with no flex. Not bad......just different. It takes a few times to figure things out when first using an injector, but not long if you're already using a DE razor. They can bite if provoked, but normally are an effective and comfortable way of whacking whiskers.
I included a few pics, with one showing what the injector blade looks like. Hopefully you can see it just has the one sharp single edge, which makes it a SE razor. My favorite injector model turned out to be the Schick adjustable. I liked being able to dial in the correct level of aggression, just as I do a DE razor. The other two short handle versions are an 'E and G type (both too aggressive for me). Heh, I also posted a few vintage and sought after blades, just in case you see any around.
Well, that's a start. If I can answer some other questions I'll be happy to try. I've used most of the injectors made, plus a good number of blades in the past. I had great luck with injectors and would be using em again if I ever quit the DE for some reason. I still take the Schick out for a drive on occasion and always enjoy the ride.
Martin