I've got the 500FF's on my roof, 4 of them. I think they're good value for the price. The pattern isn't great, but I think it's fine for a truck that probably never exceeds 70mph on the highway, or 40mph on dirt roads.
They aren't nearly as good as my FF1000's, which in turn aren't nearly as good as some Hella 4000's but... as I said, for the intended purpose and price, they're good value.
I would pass on the HID's. Unnecessary complexity, and probably lots of light you don't need. With my lows, highs, the FF1000's on the bumper and 4 500FF's on the roof, I've got MORE than enough light.
My Dad picked up some old style 500's from Walmart for $25 a few years back. Put those on his 99 Yukon which has attrociously bad lighting. Those lights really weren't great, but still probably a 400% improvement over the stock high beams. The 500FF's have an even better pattern.