Well, it was mentioned that a PTR91 would give you more use than a .22 can or NV. I disagree. I don't have my can yet (have fired a suppressed .22 on many occasions in the past, and they are very practical and useful) I do have a pair of PVS7D's which happen to have a Pinnacle tube in them which puts them on par with PVS14 with a newer .mil tube.
True, you can be Way Wactical with NVD's, but to be honest, I get most of my use with my NVD's riding my mountain bike in the woods after dark. I tear ass through a public park in suburban Detroit, pass through several apartment complexes and am never seen. Basically, there is nothing you can not do with these at night that you can't do during the day.
You will always be able to buy a copy of the HK91 (or the real thing for that matter). You will likely always be able to buy a can for a .22. You will probably not be able to afford a top drawer NVD if you shoot your wad on a can and PTR91 by the time you save enough to get the NVD's again. You need to do the smart thing and look at it as though you are buying the ability to see at night, not that you are buying a toy you can only play with in the dark. Makes it a lot easier.
I'd venture to say that a person with a set of NVD's, a few bottles of water, and a pistol or carbine could have gotten out of NOLA unharmed if the were in the worst part of town and waited until darkness to set out for safety. I look at NVD's as a tool to keep you out of trouble but if it comes down to it, nothing will turn you from a sheep into a wolf faster than having a set of NVD's lashed to your noggin.
Having NVD's means the difference between hunkering down and waiting the night out. It means not having to stay in a bad situation. With the power out, even a modern city like NOLA gets Country Dark at night... The um,... ahh,... "Natives" wouldn't have been able to see a hand in front of their face, so they definitely wouldn't have challenged the sound of a person walking down the street in the dark. At the ARFCOM WV survival forum in Sept. this year I did a demo with Fight4yourrights (who is also Night Capable) and some of the attendees. We walked up a gravel road away from the camp area, stopped and told them to walk back down the road, then come back and find me. The group walked 100 feet away, turned around and started back. All I did was step back 6 feet, staying on the road, and crouched down. They got within knife distance before I spoke up and gave myself away.
Something to think about.