Any thoughts on these Samsung 2TB SSD drives?

Samsung 850 Evo, 2TB:
http://www.amazon.com/Samsung-2-5-Inch-I...eywords=2tb+ssd

Samsung 850 Pro, 2TB:
http://www.amazon.com/Samsung-2-5-Inch-S...eywords=2tb+ssd

I'm happy with my 1TB 840 Evo that I've got in my laptop right now, but baby needs a bigger backyard. Thinking of ordering the 2TB 850 Evo. Wondering if I will notice anything better if I choose the more expensive "Pro" version instead. Any thoughts/opinions on speed, reliability, etc.?

Note: Price is only the most minor of factors. I am one of those people who is willing to pay for extra performance, reliability, convenience, or features. I still take price into account a little bit, but not as much as most people would. I'm more interested in knowing things like, is the performance difference negligible, is there something else better out there, is there a reliability concern, that sort of thing.