Either suspension is a good start on your build. I've had Old Man Emu suspension on rigs (currently set up on my '86 Toyota pickup), and Bilsteins as well. I've had more than one set of OME shocks fail (leaks) on camping rigs that carry gear for extended off highway travel.
If you're planning on extended off highway travel, I would highly recommend that you weigh your rig fully laden for travel before you purchase suspension parts. After you have a good idea about the weight you'll be carrying, you can now look at appropriate suspensions for your usage. The springs and shocks should be mated so the valving of the shocks matches the spring rate. If you plan on just driving the rig off highway on weekends and such, Bilstien 4600's should work just fine if you aren't swapping springs. I ran the 4600 B6 before and found it to be more than suitable for light to medium off highway travel.
Cheers