And with so many stellar names in the mix, fans are cherry-picking the must-see gigs from the not-so hot ones.
Slane pulled in 50,000 punters to watch Bon Jovi rock out – but the venue has a capacity for 80,000. Robbie Williams didn't sell out the Aviva, and 18,000 fans attended Neil Young at the RDS on Saturday night, a venue with a capacity for 30,000.
In fact, the only people who have managed to sell out big venues are Beyonce, Bruce Springsteen and One Direction.
But Henry Mountcharles was more than happy with Bon Jovi's three-hour set.
"You give rock a good name," he told legendary frontman Jon Bon Jovi when he came off-stage at Slane castle late on Saturday night.
The 51-year-old jetted out of Ireland straight after their concert in which he thrilled the audience on the banks of the River Boyne.
Despite Jon's departure, the after-party in Slane Castle lasted until 8am on Sunday morning as rocking aristocrat Henry welcomed guests including Minister Leo Varadkar, and the Mexican Ambassador Carlos Garcia de Alba. "I take my hat off to Bon Jovi. Not only did they do their own songs, they did covers like Start Me Up and Rocking All Over The World. The fans loved it. That's why they got two encores," Henry Mountcharles told the Herald.
However the concert boss hit back at critics who described homegrown openers, Ham Sandwich, Bressie, and The Coronas, as a "the penny-pinching support bill".
"It is extremely odd anyone would say that about supporting Irish performers," he said.
With a career spanning three decades, it seemed like one hit segued into another for headliners Bon Jovi as they delivered their American rock songbook from a Fifties-style car bumper/grille stage set for over two hours.
Stars seen in the VIP area included boxing champ Kenny Egan and girlfriend Stephanie Williams, model Rozanna Purcell and former Ireland soccer star Gary Kelly.