they do feel weird when you first use them! make you dribble uncontrollably too :p
i used a philips sonicare for about two years before it died and then i couldn't bothered to spend £100 again (and also the expensive brush heads), so went back to manual. even though i was saying that my teeth 'felt' cleaner with it and i was sad to go back.
i would say it depends more on your brushing technique than whether it's manual or electric.
since i've started going to the hygienist and she's taught me the 'proper' way to brush, i've felt happier with using a manual brush but also, the 'proper' way does seem like it would be easier with to brush with an electric brush, so i might go back to one.. but i don't think it's necessary to buy such an expensive one.