Go ahead, do it, use Dropbox. That way, you'll find out about the following features:
1. The rest of your internet doesn't work. Nothing. It all slows to a crawl. This despite you believing you have chosen settings that don't hog all your broadband: you haven't and it will.
2. Lack of speed. Despite taking up all your broadband, prepare yourself for multi-hour uploads and downloads. Sure, some of this is because of your crappy broadband speeds in rural wherever, but Dropbox isn't going to help you any in this regard - I don't know how or why they choose to make everything so slow, but that's their gameplan and they're sticking to it.
3. Notifications - they're great. I mean, you have a shared folder or fifty now that you have been using the system for a while - what you need is Dropbox telling you all about every single change to every single folder via annoying notifications on your desktop. Possibly there is a way of turning these off but see 1, a…