I have experience w/ the RC 6.5" kit and I did the original write up on their drop brackets here on this site. (Do a search for Rough Country drop brackets or go to RC's website and look at the link under the drop brackets that says something about a customer install, thats me!) I ran the kit for about 2 years, one of which had the drop brackets. The upper and lower control arms were a bit simple/light for my liking, but RC has the new upgraded flex joint control arms that are of good quality (just put some ona buddies rig a few nights ago). I wheeled the bag off of that kit and had no complaints.. I wheeled rock, trails, daily drove it and some mud (I hate mud for the record). I can say that the price and their improved quality and customer service is great at RC. I have no experience w/ IRO stuff, so no input from me pertaining to that. I have since upgraded to a TNT Y-link kit and am no longer running the RC kit, but it has been passsed down to a fellow wheeler and he is still wheeling the piss out of it as well. Dont be afraid of RC, they are a company that has improved with time, and are a company w/ products that should be considered in your decision making.
One last thing, I also support Rough Country products b/c they are a big supporter of this site/organization and the functions that we put on. Support those that support us!! :thumbup: