It was my choice of area in the early 00's - mainly because it was near my work.
The only other high density area, was/is the Earls Court area.
Hard to tell which was the smarter area, both had very shabby parts.
I remember Crawford Street, off of Baker Street got quite busy in the mid-00's, which was even closer to work.
There was this one flat, just around the corner from my work, that I must have visited 15+ times over the years - seeing Indy girls and all manner of Agency girls.
At about the same time, just around the other corner was Marylebone High Street, where LMP used to be.