The oneblade uses a blade that is hard to find and quite expensive...of course you can buy the blades from them, but at that point, you might as well go with Gillette cartridges. Just my opinion of course, but part of the appeal using old school razors is having seemingly endless razor blades to choose from at dirt cheap prices.
If you want to try a single edge razor, try a vintage SE razor or one with an injector system.