I've never used one but they're about to become optional where I'm at. What's the general opinion from you guys that use them?

How do you use a plate carrier with them?

I'm confused. Why aren't you putting the stuff you'd want on your LBV ON the plate carrier?
edit: I guess that you're referring to the external soft body armor carriers, not plate carriers.
I've transitioned none of my daily equipment to the external soft armor carrier.
I expect to don the hard plate carrier as time permits in a serious event.

I wore a Point Blank Maverick MOLLE outer vest for a while.  It had my soft armor in it and had pockets for rifle plates.  I had my Taser, radio, and cuffs on it.  My pistol and pistol mags stayed on my belt.

I have no idea what the vest is. I just started with a new agency, and they told me we would be fitted for "load bearing vests" as patrol vests. The Officer I talked to wasn't sure if the make or model, so I don't really know what to expect. I guess when I heard them say "load bearing vests" I kind of assumed it would look like the old static Blackhawk vests that everyone used to have, except that these would obviously also hold soft armor.

I really, really don't want to wear rifle plates around 100% of the time, lol.

Where on the vest did you put your stuff?

I've seen a couple different types in use, some were:

Just a mesh LBV that had mollie strips all over it, which the officer wore over his normal uniform and vest.

An external vest carrier (more like a tactical carrier) that had pouches on mollie strips, and had plate pockets on the front and rear.

And I saw one cool set up that looked like a uniform shirt type of carrier, but had some pouches sewn into the lower half for mags, and such.

Given the choice I would go with the second option and have the plates handy for bad situations.

JG Uniform in Chicago does ours. It has four rows of molle along the lower half and two shirt type pockets. I run my mic cord inside the vest. They are awesome and allow you to carry stuff like touriquets easier. My gun and baton are the only things on my belt.

They are expensive and I scotchguard mine to keep it cleaner and protect from uv rays (fading).

It is awesomely good. It has pockets front and back for rifle plates, but you probably would have to let the sides out after putting them in.