Drubs what do you mean by mild?
When a razor is described as 'mild', it mean very little blade exposure. Also that you have to dial in your shaving angle more precisely and have it bang on to get a decent shave.
Because of the angle you are restricted to, it may mean less DE blades work well in that razor.
If you have a fast growing tough beard, 'mild' razors aren't usually well suited. They usually take an extra pass or two, a definite ATG pass, and some touch ups
I can shave well with a feather blade and a Tech, don't get me wrong. I sometimes do get out a milder razor for a change and I can get it to work, I just prefer more aggressive razors.
If your facial hair is about the same as body hair, any razor will do the job, I stick to the aggressive end of the scale because my facial hair is dark, thick and tough.
Going on the Slim, the blade gaps are quite small, and the geometry of them makes them feel less aggressive.
If you want to try one, you could probably pick up a good looking Tech for $25. THat one is just a fancy plated one I think.
Standard Tech was the first solid safety bar a 3 piece razor; the ranger tech is one of the first TTO solid safety bar razor not sold in high numbers because of WW2 (along with the regent, milord, aristocrat). It kind of was around for a bit, then redone as the 1940s superspeed after the war, while the basic 3 piece tech was made in high volume.
edit: Look at mr-razors site: Not much in examples for TTO made between 1941 and 1946
http://mr-razor.com/Rasierer/One-Piece solid guard bar/solid guard bar.htm