All depends on what your plans are and how much you want to spend. A few of the companies offer bolt on or weld on bars. And a few offer blocks incorporated with the bars if your plans are to lift the truck and keep the factory load setting and good ride quality. Form what I've seen along with price comes quality.
I personally went with OUO Traction bar/blocks with 3/4" u-bolts because I didn't want stacked blocks and from the recommendation of other members, all of their stuff is engineered to last and out perform the competition. I purchased them through Truck Toyz Performance who has great customer support. The person who filled the actual order in the warehouse put in the wrong length ubolts. I called them and they had the right set there in 18 hours. Mistakes happen. It's what the company does when that happens that can set the tone for future business.
I haven't tried any of the other set ups, so I'll let guys that have, talk about their own.