Also check out Rubicon Express's 4.5" lift for ZJs. I ran this on mine for years without issues. Generally, the long arm systems will give a much smoother ride for street use.
There will be other things to consider, like drop steering bracket, extended brake lines, extended swaybar end links (or like others, myself included, get swaybar quick disconnects for front, extensions for rear), Steering stabilizer. There may be other things I'm forgetting and hopefully others will chime in.
Of course you have to factor in new wheels and bigger tires
Like hound said, take your time, pick the lift that best suits you in the LONG run and buy accordingly.