Rolf,

Yes - I should imagine they are if the reviews on the links Masato posted are anything to go by. I actually prefer Son House and some other Delta blues singers to Robert Johnson, who I see as a great musican, but one who has been put on too much of a pedestal and subject too a lot of hagiography.

It can be hard getting some blues records in the UK, although there are some good music shops if you look about.