Hi, I'm thinking about switching from Win7 to Ubuntu. Will it be faster on my Dell Inspiron M5030 laptop?
Linux has better memory management and more hardware support, so I'd say yes. But if you are coming from a Windows to Linux it's better to try
Zorin OS. It's really Ubuntu with a different UI and it comes with Wine. Wine let's you run windows programs in Linux, but it's more designed for games.
tl;dr use Zorin OS if you want it to look like Windows.
Also install it to a USB, and try it out.
Pro tip: Run Additional Drivers to get graphics drivers.