I don't believe it's 22 GB of data per line. I think it's a 22 GB bucket of LTE data for all lines to share and then after that, your speeds could be throttled but you won't have to worry about data overages. Also, keep in mind that you cannot use Personal Hotspot on the new AT&T Unlimited plan.
That said, I switched two lines from Verizon to AT&T last year and I have no regrets. The employer discount I get through AT&T is 24% vs. a puny 6% with Verizon.
I have 6 GB of data with rollover and while traveling in Canada and Mexico, I have unlimited calling and texting to numbers in those countries and also back to the U.S. I also have 1 GB of data per line per month to use in Canada and Mexico. That's all included with my AT&T Mobile Share Value plan. You do have to call and ask the AT&T retention department specifically to add the Canada roaming bonus to your plan but they'll gladly do it in my experience. You can add the Mexico roaming bonus through the AT&T website.
Verizon is simply not coming anywhere close to matching what I can get with AT&T right now for the price that I'm paying.