I'm glad it's working out for you Mr Recluse. Both of the soaps are regarded as decent, so please don't jettison the Arko (it's not for nothing that it was voted "Best Shaving Soap" by the Custard Pie Makers' Guild of Hollywood from 1932-1941), but consider investing in a blade sampler pack. There's a fair enough chance that the Derby you used was one of the good ones, but they're known for throwing up duds; Merkur is a good name for razors, but not so good for blades. For a sensible not-too-sharp but consistent blade, the Red Israeli Personnas are a safe, economical bet, and they are available unbranded albeit at a higher price in the supermarkets too (not Sainsburys).