I just watched the Bradly Cooper/Gaga version on HBO. I liked it but it was very dark......visually and emotionally. I thought Bradley Cooper was just fantastic! I wouldn't have thought he had it in him - but he did. He really looked the part too.....tired, aging out rock star on the decline. Booze and drug addled, but with a lot of charisma.
Gaga - I think she did ok, I personally don't think she's a great actress. Some of the lines she had, they came across as flat. She didn't pop off the screen for me.....Cooper did. And he didn't have to say much - his expressions said it all. He had the right look.
My favorite version is Streisand/Kristofferson......damn they nailed it! Kristofferson was both rakish and charming and very believable in his role. Both had the chops and talent to pull their roles off.......very opposite types but they has great chemistry - and that film was brighter......and by brighter I mean color and light. It was just visually more pleasing, and if I remember correctly, Streisand wore much of her own personal wardrobe in her version of the film.