Great place, each bar has live music, great musicians. The best music scene ever. My advice: go to Magic bus tour, with their tickets from a tour, which are not expensive, you have 3 free entrancies to Cavern Club. Next advice: go to the bars at 9 pm, that's when live music starts and it usually stops at 11 pm.
You won't be able to leave that place next 5 hours, believe me