Everybody hated on short arms when I bought them. In January.
Yeah.. this last january.... 2008.
I bought them anyway.
I didn't like them. They worked really well, in terms of articulation. If you go short arm, make sure you get adjustable with an articulating joint. There were a handfull of other factors that went into my change to long arms too, so I can't say it's all about hating the short arms. If you don't drive your ZJ a lot, you'll probably be fine with short arms.
I just read the install instructions of the Rusty's kit. It Bolts on. Yeah, you could weld it on too, but that's just scary that they reccomend it to bolt on. It also retains the rear track bar. To be completely honest, I'd buy another Rubicon Express short arm kit before I'd buy Rusty's long arms. PM Wayne Heartwig. he'll get you a deal on RE stuff.