I have had my AC 3" lift for 3 years and around 65,000 miles. It has worked well for me....on-road and off.....for that time.
Some have had indications of alignment difficulties do to the upper control arms being a tad too long to permit proper camber adjustment....but I have not experienced that with my lift, and I am still running my BFG AT street tires 50,000 miles later, with no weird wear patterns.
EDIT: Upon re-reading this, I do want to clarify the comment on the upper control arm length issue.....Some people have reported difficulty in alignment due to the UCA's being a tad too long (I believe Carlton was one), but I did not experience that, and I believe AC has remedied some time ago, any problems that may have existed regarding that matter.