I had these in combination with the Rubi rails and absolutely HATED them. As a result of where they mount (below the rubi rails) they lessen your ground clearance compared to most other rails.
I was constantly getting hung up on them and my spotter would always be yelling 'on your rail'.
That said, if you are doing light wheeling, sand dunes, fire roads, etc, they will be just fine. They do make a great step and will take abuse. Just for moderate to heavy rock crawling, they absolutely SUCK.
Here's a video of me when I had the Ace rails doing some rock crawling:
http://www.youtube.com/watch?v=dAf9Oo3I7fU
I got rid of them for the Evo weld on. I couldn't believe how much easier rock crawling is when I wasn't getting hung up on the Ace rails.
Additionally, they do come powder coated, but if you use them, the powder coating comes off really easily. I was constantly touching them up with Rustoleum. I have to touch up the Evo a lot, but even the Evo powder coating (which isn't that good) is much better than the Ace.
If you must have bolt on, I'd also suggest the LOD. They were my second choice.