I bought a bunch of old vintage razors, mostly swedish, british and german ones that are considered top notch brands of their time; but since they were between 50-80 years old they weren't completely straight (dropped on floor?), so getting a good clean angle on them was hard. I have been able to shave with them quite well, but even though I take pride in my sharpening abilities I feel that I need to buy a brand new one to know that I'm not doing something wrong or if it is the razor itself — cuz they are bent and mistreated.
I second getting a mechanical straight razor which takes DE blades (you snap them in half in the paper). It is a very cheap solution, you don't risk cutting yourself as deeply and you know that the razor is in order (sharp as hell). By knowing this, you can single out your problems more easily (lather, beard prep etc). Do it.