Example: Will a Healthy White 4 toothbrush clean as well as a Sonicare Diamond Clean as long as they both have the diamond clean head?
Look on amazon's product page for those toothbrushes. They have a chart indicating the differences. But it seems like the major difference between models are the brushing modes.
I agree. I have the Phillips Sonic Care (e series, which I don't know if they still make those something like this) and my impression is that it will clean your teeth just as well as the Diamond Clean. A quick look at those two pages (that I bothered to link ) and the main difference are the extra cleaning modes of the Diamond Clean. Healthy White vs Diamond Clean
They're all pretty much the same, except for the rhythm cycles the handle can produce. I'm on my fourth model now.