I admit I thought about ditching unlimited data and going to the mobile plan. A couple weeks ago or so, I was on the phone with AT&T, finding out about my options about paying off the 12th month of Next. I asked him about the mobile share plan. He actually told me that with my data usage between iPhone and iPad, which was 13GB the last full month before then, that it would not benefit me at all to ditch unlimited. That convinced me. I couldn't even fathom that an AT&T rep would tell someone to stay where they are and not pay more through the MSP
This makes sense if you are on a single line, not so much if you have more than 1 line.