If the main goal of the RSVP system is to decrease chaos, camping, and long lines at the stores then I'd say the twitter system is successful.
But if the twitter system is to ensure equality and that everyone has a fair chance of getting their pair, I'd say it's a failure. I don't know for a fact that this is happening, but in my mind, the person in charge of the twitter account has the ability to register whoever he/she wants for the pairs since everything is virtual and no one can actually see who registered first. For instance, I was able to RSVP within 40 seconds for a release but didn't receive a pair. I can totally see the owner of the twitter account just going through and picking names he/she recognizes or his/her friends.
I feel like this new system just enables too much shadiness as people don't know what's truly going on. But I guess that's the price you pay to prevent chaos.