Steal Plates are twice as heavy, or more as Ceramic, there alot cheaper, but then there's the chances of Spauling. I guess having your jaw replaced is better than being dead. People say soft armor over steel prevents spauling but thats a myth ive seen busted on youtube (if it's on youtube, it has to be true). pretty sure steel will stop just about anything except the 50 bmg.
Ceramic is very light but extremely expensive, will stop up to 30.06 depending on level certification. No spauling of course, but people say they have a shelf life, not sure if thats the certification expiring or if the ceramic actually breaks down over time??. Like anything, it depends on what u want to spend. You have to stick to the big name brands because there is alot of fakes out there, you get what u pay for. People will claim level 4 certification plates for 300 bucks, but would u be willing to trust your life on it?? The real certified ones wil set u back near 1k a pop.
The way i look at it is, if the SHTF most everyone will have AR's and AK's, so plan for the worst. Level IIIa stand alone plates will surfice. Some plates you will need to pair them up with soft armor to get the Level IIIa or level IV rating. So i say go with stand alones and your GTG. There's alot to know, so do ur reasearch if ur serious about getting some.
I'd get a plate carrier, you'll need the molle pouches to carry all ur magazines and ammo.
Contact Body Armor Outlet in NH, atleast one of the saleman are NES'rs so they can hook u up. Tell them ur a NES member.