I love all of them! Gaga is the one who I personally feel has helped me the most throughout everything I've been through. I'm kinda gonna go off topic for a moment but have any of you heard Autobiography by Nicki its amazing and quite different to what Nicki normally releases?
IT DOSNT MATTER WETHER THEY WRITE SOPME OF THERE SONGS OR NOT, sorry for shouting wanted to get your attention, gag saved my life but nicki helped with my confidence she is insirational, you cant say she isnt, yeah not every one of her songs has a deep meaning but they still make me feel, they make me smile, stop slagging of other artists and respect them for who they are other wise how can we expect non-little monsters to respect Gaga?
Rihanna throws out songs so fast because she doesn't write them. Since they're already written she can just go and sing them and release, with people who write their songs it's much more of a process, and takes much longer.
If you want to create something new and something individual, it takes much time. That's why Gaga didn't release ARTPOP yet and at least, she writes all her songs by HER own.
Rihanna and Nicki are selling a product so you can consume them. The faster they release singles, the faster record company can take your money. You expect Gaga to do the same and you get frustrated when you don't get your product right away. I would say the record company is a bit pissed too, they want hits, hits mean sales, and they mean more money for the fat cat.