Basically Bradley Copper is a big time troubled star, who meets an aspiring singer who ends up becoming a star, but it all wrong from there. It's great acting but I just wasn't moved maybe it was too emotional and I was tired. I'm not sure why, but it didn't resonate with me. I just found the beginning very slow and it didn't get any better. I stopped watching it when they had a duet at the concert.
What I did find out was Lady Gaga wasn't the great singer I thought she was. She is very good but without her 'Lady Gaga' persona and the electronic music etc, she was just a good singer. I was expecting some really really good singing. But no. I still like her but doing 'Lady Gaga'. She's more or less a studio recording artist. Funny that.
However her acting was very good. Better than most singers-turned-actresses.
I guess if you want an emotional weepie or like a good drama with something to cry about, watch it. Some good films are hit or miss for me, and this was a miss for me. BUT IT WOULD BE A HIT FOR MOST.