When I was a mouse user, it would take ages to get 100m points, but after reaching 400 after 5 months,
I got a wacom bamboo MTE450.
Since then I reached the #9999+ ranks within a matter of weeks and gained many top 40s (also achieving 500m points within a few days).
A tablet is definitely the fast track to becoming pro, but mice are harder and take much longer to become pro using, but once you do get good with one, you can get great accuracy with them as opposed to the tablet.
And as Cookiezi said in the osu!monthly, good hardware is half, skill and experience is the other half.