I don't find vibrators do much for me (a guy) in penetration, but maybe they haven't been strong enough. I have one for my masturbator thing though, that's pretty good but not comparable to a dildo. My partner (female) prefers vibrators if we're using toys.
I like both -- doesn't matter whether it's a dildo or a vibrator, the most important thing to me is how effective the toy is. My favorite dildo is the Njoy Eleven, and my choice vibrator is the Jopen Vr5.5 rabbit.