I'd say the comparison with Britney is very unfair. From what I've heard, Lady Gaga's eccentric style is more a product of the influence one of her friend's that passed away, rather than under instructions of her record label as a cheap gimmick.
And looking at the actual writing credits for her most famous records, she is listed as co-writer on all of them, as opposed to Britney, who isn't credited as having any input into the writing of "Toxic", in fact it was already completed and offered initially to Kylie Minogue, who rejected it. Same with "Gimme More", she didn't write that either, just recorded it.
I'm not really a fan of the girl, but she does write some very catchy songs and for my money, is without a doubt one of the best mainstream artists in Pop.
Hello mate!