One problem I have found with my new Lenovo ideapad 100 15iby running Elementary OS Freya is an issue with the mouse pointer vanishing, as reported here. It seems that if you lock the machine, close the lid, or let it go to sleep, then after signing back in there is no mouse pointer. It's annoying because neither the trackpad or an external mouse seems to work.
Anyway, the solution which seems to work for me is just to replace Light-Locker with Gnome Screensaver. It means that the lock screen is not as pretty looking, but I'd rather have a mouse that works!
It's an easy fix and worth it, although it looks like future updates won't suffer from the same problem. So I look forward to trying that out when I upgrade to Elementary OS Loki. But I'm waiting for it to be released rather than using the beta.