I've been a longtime user of SonicCare brushes. If you are getting great results with a manual brush then an electric toothbrush is not for you. It is a little harder to get into your mouth than the old manual stick brush, and there is only so clean you can get any surface. So, if manual gets you completely clean twice a day every day with just two minutes of brushing, more power to ya.
For me, though, the difference has been night and day. I used to have horrible dental hygiene, which I am still paying for (massive fillings I'd gotten after neglecting my teeth through much of my young adulthood have reached end of life and are needing to be replaced with crowns, which are a pretty massive chunk of change per tooth). When I switched from manual brushing to really diligent flossing and my SonicCare brush, the cavities-per-year went down to essentially none (what cavities I do get now are due to the aforementioned fillings deteriorating, which is not something that can be stymied with brushing).
That said, I'm not seeing anything in this more-than-twice-as-expensive kit that would improve my personal dental health. I have a good routine down and almost never miss brushing, so any kind of "achievements" and such are lost on me. Every indication from my dentist is that my toothbrushing pressure is perfect. The "too little time on that tooth" indicators might be helpful, but I'm not sure I'd trust them yet (remember those little red dye packs that you had to chew and then brush until everything was clear on every tooth? Seems like that's the only approach that is actually going to capture missed teeth reliably). I might try the next generation though when it comes out two years from now.
As for electric toothbrush head costs: I tend to average about $8-10 per head buying in bulk (name brand SonicCare; you can find off-brand brush heads for a few dollars less - quick glance at Amazon shows them as cheap as $1/head - but I figure it is a low cost to begin with). I have a reminder on my phone that goes off every three months to remind me to change brush heads (another thing I don't need the app to tell me to do...), and the first brush with a new head is always a revelation. Yeah, that $40/year is more than $5/year you might spend on manual brushes (also should be replaced every three months), but barely a drop in the bucket of the overall costs for dental care (floss runs about that same $40 per year, for instance, and dental visits are either about $300/year for just cleanings and checkups or about $300/year for individual insurance which covers those cleanings and checkups 100% plus any corrective action necessary...) I just don't see toothbrush head cost as a major factor in choosing between manual and electric toothbrushes. If it improves how clean my teeth get, or how often and thoroughly I brush, it is worth a few hundred bucks easily.
