The set up itself is fine and dare I say it, easy, if you know what you're doing. Takes a day or to get the gearbox in with the electrical system in place. You'll need to bang away at the trans tunnel to get it to fit. You need roughly 1-2" clearance around several parts of the OD but it can be done easily, just awkward I guess.
If you're thinking of going for the Auto-shift unit wait for a few months as GVs "discovered" some faults in the existing module so have taken it off the shelves and are going to fix the fault. It usually runs of rpm signal through all shifts but we/GV discovered that the best way to do it is to run it off rpm until the final OD gear which it will now run from the speedo (in OD only) just like the stock unit but only in the final ratio. Awesome unit, I've been having a blast even though I have to click a switch for the final OD to hold it in until the new modules are ready, that was the main fault, kicking out of OD in the final gear around 5 mile intervals.........IMO you should absolutely go for the auto-shift module unit, no doubt.
Good luck.