Re: Superspeed, Mekur HD and Mueli R89 Open Comb
Technically, it shouldn't be massivley more aggressive than a modern open comb Merkur as the heads are pretty much the same. That said, it is slightly heavier so a bit of caution is required if you're used to lighter razors. I find that open combs have a bit of a bad rep when it comes to aggression but they're not half as bad as they're made out to be.
My mate's first safety razor was an R89 and it's a great looking and great shaving razor. He has never had any problems.