So, do you use them with minitures when running your game as combat breaks out, or do you hand out maps and roughly adjudicate character placement in rooms with covered distance being fairly subjective?

I've always enjoyed being able to simply describe things to my players, but maps and grids make things a lot more hands on...however they do tend to bog down gameplay. Anyone else?

I've done both. My group usually uses grids, as it's what we're used to. They aren't really necessary, and in some cases can actually hurt the process (such a when you're fighting at rifle ranges instead of pistol ranges).

When I ran at GenCon I brought pre-drawn maps with me on large graph paper with 1" squares. Of course, I promptly forgot them in my hotel room and was forced to improvise with hand drawn maps for approximate locations. It worked fairly well.

We've invested in a 4 foot by 3 foot wipe clean mat marked out with inch hexes, combined with dry wipe markers and a variety of multicoloured tokens it's very useful in large scale combats.

We generally use 1 hex = 2 meters.

1 square = 1m is what we use unless the ranges open up more, then it's 2m or 3m per square.

I like to use a 1" wet-erase hex map.
For long distance outdoor stuff I don't bother with hexes, but there's always a map to point to. The hex map is mostly for combat. Usually 1hex=1meter, but it changes as necessary.
It adds a bit of work, admittedly, but I really hate the type of arguments that arise from PCs and GMs misunderstanding each other, and it helps with that. It adds another dimension for them to plan in, and overall I think it adds a lot to the game.