I'm new to the Oneblade, having recently bought a second-hand v1. I'm really enjoying it. I despined a GEM razor to try, and yes the shave was OK, but the whole thing gives me the willies. I don't believe I'm going to hurt myself with it, but it definitely doesn't feel secure. I don't think I am prepared to nibble the blades to lock them in, it's just a step too far, and it's a shame to using such a nice razor with an unsecured blade.
The whole thing hinges (boom boom) on how many shaves you can get from a Feather I guess. I've just had my 4th shave off a Feather blade, and I think that was the cutoff point for me, so I'm going to stick to 3 shaves per blade. On that basis, it's still more expensive than DE shaving, but it's not going to break the bank.
Connaught's cheapest makes this 14p per shave for me. That's about 4 quid per month. I think I can live with that.