Can i answer all of the above?
The reason i say this is because each bit brings me different forms of enjoyment.
When I'm using a dildo/vibrator, i have found that i do enjoy vibration, especially if i'm able to angle it to hit my prostate. the vibrations cause a huge sensation to flow through me and it's almost electric. However, when it comes to insertion/removal, vibration really doesn't really do much for me. I prefer something that has interesting textures or is medium to large. the largest i'm working with right now is one of the 9" raging hard ons dildos. the veins have a very distinct feeling.
Plug, i do like, not quite as often, but i do like them. i'm in a long distance relationship right now, and when i get to see my boyfriend, we tend to frequent the bedroom. He's rather large, and because i dont have time everyday to play with toys, i tend to tighten up. So i use plugs to get ready for him, sometimes wearing them to the airport. I'm currently getting ready to try out one i just bought last night, its an aluminum plug from Cal Exotics.
i use a little bit of everything for different reasons, there's no one specifically that i enjoy more than the other. =)