Something that amazes me about Bester's writing is that neither book feels dated. Then, you think about how visionary he was in the time they were written, and it blows you away.
Of course, the other thing about Bester that amazes me is that he's so obscure, despite as you point out winning the first Hugo and for writing notable early sci-fi. Someone's knowledge of Bester has become an informal litmus test for me to get a feel for how well read someone is in sci-fi.
Neat tidbit about Bester: he's also credited with writing the Green Lantern Oath.
edit: to be specific, Silver Age Green Lantern.