I had the same problem. I was brushing too hard, causing my gums to start to recede. I thought an electric toothbrush would help, so I got a Sonicare (Philips) but it did more harm than good. The Sonicare head mechanism was too large to easily brush my back teeth, and I ended up needing my first (and so far only) root canal in one of those back teeth after about two years of using the Sonicare. Also, the Sonicare's type of vibrating motion really wasn't that effective at removing plaque, at least for me. I basically ended up brushing as aggressively as I did before, which didn't help my gums. After the root canal my dentist suggested going back to a conventional brush using an "ultra-soft" tip. That made a world of difference for me. It keeps the teeth clean while being very gentle on the gums. Ultra-soft bristles seem to wear a little faster than soft or regular bristles, but they're still a whole lot cheaper than an electric brush and replacement heads every so often.
I don't have any experience with the "rotating head" style of electric brushes. Those might be better for your gums than the Sonicare style head.