Stand alone plates (IV) vs. Plates III + backers

Okay looking for input from people who wear these every day. I am trying to decide whether I should get a set of stand alone IV plates or go with a ESAPI III plates plus backers. This would go into a Mayflower LPAAC.

I am just a civilian puke who goes to classes a few times a year so I am not going to wear this constantly. But I do want comfort (and safety obviously) if the zombies come and I do decide that its now everyday essential.

Cost is of some concern but not critical - safety and comfort come first.

If I do the III plates + backers I'd go with the Velocity Systems stuff (since its cut for the LPAAC).

Thoughts?

I only run the Lev IV stand alone plates. I don't want the extra weight of the backers and I don't wear the side panels, just front and back plates. I prefer the mobility of just plates over the limited Lev III protection in the sides and it also keeps me from adding more stuff I don't really need to my kit. Regarding the backers...I've never worn them for that purpose so I can't comment on them other than the added weight. Resale of Level IV stand alone plates is generally better from what I've seen if I decide to get rid of them.