Is there any advantage to stay on the OLD mobile plan vs NEW?

I have been on the "old" mobile plan since the service was launched and have been very happy with the service.  Initially, with the two lines, we were only using 1 or 2 gigs per month because we were home most of the time so that was only $12 or $24.   It started creeping up a little bit so where it was usually at or under 3 gigs so I have been using the $30/3 gig plan, but sometimes we are at 5 or 6, so the last few months, I have just had it on the $60/10 gig plan.  Something does seem a little off though because my wife's iphone seems to use more data than it should, considering she mostly uses it at home (I made sure the setting was off to use data in areas of weak wifi), but that is another story.  Anyways, if we continue averaging 5 or 6 gigs per month, that $60 is the same as the unlimited price on the "new" plan.  It doesn't seem like we are ever going to only use 1 or 2 gigs per month again, so is there any reason or benefit to stay on the old plan?