What helps is a generally excellent song lineup. you can't like them all, but i dislike maybe 3. Also, the theoretically unlimited song base makes for great game lifespan since you can download new songs off Xbox Live or whatever console service you're using, not to mention additional full games like the Rock The 80's Edition that came out a week or 2 ago.
The jump from easy to medium isn't so bad, but wow am I getting manhandled on hard. i keep losing my bearings when i move down to the 5th button.