I don't mind whether rechargeable or battery operated, arguably battery has some advantages - if the battery is flat at least you can just pop new batteres in and use immediately, but if you discover you've forgotten to charge up your rechargeable appliance I imagine you need to wait at least an hour before you can use it. Granted a timer would be handy but not a deal breaker, it's not difficult to work out when 10, 20, 60 seconds are up - otherwise have a timer/watch handy. The warning about using close to the hairline I imagine is to avoid getting your hair caught and I presume that's just as possible with a Clarisonic. Personally I wear a hairband to keep my hair off my face when I'm doing my skincare so again wouldn't bother me.
I don't think the Boots one had an inner removeable section, but the brush diameter I'd say was 25-30mm which looks to be about the same as the Clarisonic inner circle (only basing that on pictures of the Clarisonic though, haven't seen one in the flesh).
Will the Boots one still work 3-4 years later? Maybe not but at £25 -v- £167 it's a chance I'd be prepared to take, especially when there's a risk that after the initial novelty had worn off there's £169 worth of gadget resigned to the back of the cupboard.
