I still get the old-style suggestions from time to time. It seems like the functionality is still there to display videos related to the one you're watching, but half the time it displays the same mix of recommendations you get on the youtube homepage. I'm not sure what it is that triggers the related video recommendations instead of the "personalized" recommendations.

I went through a "This Old Tony" binge a couple months ago because i stumbled upon one of his videos and youtube kept recommending more. But that seems to be the exception rather than the norm.