I am a longtime Dropbox premium user. I migrated all my data away from Dropbox onto SkyDrive for about 4 months as I purchased a 100GB SkyDrive account when I upgraded my (then) main PC to Windows 8.1 from 8.0. SkyDrive is forced down your throat and it does actually make sense to adopt it above offerings from rivals such as Google Drive & Dropbox due to the integration with all your Microsoft products - until you realise it doesn't fucking work properly! SkyDrive is so unintelligent when it comes to managing your data!
I own quite a few machines (Windows & Mac) and run various VM's (Windows/Linux) and Dropbox just worked beautifully. So lets talk about my SkyDrive woes. If I powered on a machine that hadn't been online for a while (lets say for more than 4 or 5 weeks), it would recognise data that I had deleted on other machines as "new" and instead of deleting it from the machine that had not been online for a while it would actually pull the 'old' data into my SkyDrive account and sync old deleted data across all my machines. This was infuriating and I took to Twitter to have a whinge (as you do). The Official SkyDrive Twitter account quickly followed me on Twitter and attempted to help me with my problems. I was then in touch with SkyDrive support and to cut a long story short, they couldn't resolve the problem. SkyDrive is too fucking dumb to recognise what is old and what is new which surely defeats the purpose of having it!
So I moved back to Dropbox and everything just works. Dropbox also has LAN sync which Google and Microsoft still fail to include with their services.
Sure, Dropbox may cost a bit more but it works and that's all I care about.