You can probably do the same (or similar) thing as them on your Lenovo tablet, if you can find the apps. Good tablet apps are still rarer for Android than they are for the iPad. Many are just super-sized phone apps, which is a bit of a let down. It's getting better though, or so I hear.
What your fellow students have probably done is convert the PowerPoints to PDF files. There are several ways to do this. Once they are in PDF format there are literally dozens of PDF annotation and note taking apps out there; several designed with the student in mind. It is also possible your college uses special software like Blackboard Mobile. If so, you can get the companion app and register with the school for some nice tools.
Search around the forum for subjects like college, note taking, etc. and you will find plenty of suggestions for apps. Do the same thing on a good Android forum, and the internet in general.
Those same students would probably be happy to tell you exactly what software and methods they are using. If you can find other students with Android devices, they would be worth taking too also.
When done, you'll have a better idea of whether it is worth your while to switch, or whether you just need some different apps for your present device.