My dentist, once I finally got a good one, first recommended an Interplak. I used that for a time. It was OK, but tended to shed bristles. A couple of years later he said that Sonicare had come out with the Elite model, which was a great improvement. He recommends that now. I've been using it for a year and a half, and checkups have been slightly better than they were after using the Interplak, and much better than after using a manual toothbrush. This is judged by the amount of picking that the hygienist has to do while cleaning.
It doesn't really matter, though. Brush regularly with what you have. Use soft bristles and brush longer. The most critical thing to do is find a good dentist and hygienist. Brushing doesn't get deep enough. You need that professional cleaning done by someone who knows how to do it. I spent years going to the wrong dentist and just about ended up with a terrible case of periodontal disease because of bad cleanings. Only the fact that I'm a good, regular brusher and flosser saved my teeth.