I have no love for Booker at all
I feel like people that say this just are completely unfamiliar with his record in the Senate. He's more liberal than most Dems at least if you believe the ideology tracker. Among other examples, he supports universal single payer while most Dem senators don't, supports campaign finance reform, and he's a sponsor of the bill to overturn the section of the Voting Rights Act that was struck down.
No his record isn't perfect and I'm not a fan of how much money he gets from corporate sponsors, but the fact that he has actively worked on legislation that would hurt those corporate donors makes me think he's on the right side of things. But I suppose we'll see whether he goes all in a small donations only type funding scheme when he runs for reelection in 2020