Speaking as someone who has had a custom long arm 5 link rear 4 link front system made up by ORI, and engineered, I can say it's well worth it if you're after if for a specialised application. IE you want to build a hard core comp truck. Probably not worth the effort for your every day offroader though, as you can get off the shelf/bolt on stuff for a reasonable price nowdays.
There's quite a bit of work involved in getting it all setup right so that it drives well on and off road. We've spent many a late night hour working on my truck at the workshop to get it so it has both on road manners and will go over almost anything offroad.
The travel I get in the rear is amazing. TJs generally flex really well in the front, and the long arm 5 link has improved on that even further. I'm still waiting for the springs to soften up a bit, and to replace the brake lines (again) to get the full potential out of it as they're the limiting factors at the moment.
