I've had a few off road capable rigs, RZR, CJ, square Burb, my daughter had an XJ, and I've had more K5's than I can remember.
What kind of wheeling you'll be doing determines what kind of rig you want. Fire roads, mud, forest, swamps etc all require different setups. See what works for others going where you want to go, and find your own variation on that theme.
Also as stated before, buying something done is usually quicker and cheaper than building your own, but it's less rewarding. What's important to you?