I find asimov to be overly wordy and rambling, especially the foundation trilogy.
However, I do not put him in the same category as Ayn Rand for wordiness, at all. I think Asimov's words really do function to build upon the foundation of his novel, where Rand just kind of spews her somewhat naive ideology in long monologues that could really be coming from any character in her book. The reality is that she just uses the characters to spit what she wants to say at you.
Asimov, on the other hand, really builds a lot of story and imagery into his work. His characters are very much unique from each other.