(NOTE: IV = 4 ; VI = 6)
I have owned both of these antennas. For my money, I wouldn't look any further than the Moonraker IV. The VI is only an extended version of the IV, with more weight.
You can download the manuals for both here: http://www.cbtricks.com/ant.htm
The Moonraker VI is a big, long antenna. They should have used a larger boom! A minimum of a 2" at least. The fiberglass boom supports break over a period of time. The hardware to secure these fiberglass rods are also a nightmare. I threw mine away and used Phillystran
to support the boom. Once up, the Moonraker VI worked great, but what a nightmare! Mechanically, it is inferior to the Moonraker IV.
This is not to say that it is a bad antenna. Performance wise, the VI performs as advertised. But in the end, you have a big antenna fed with a gamma match (lossy). You could do better!
I would ask, what do you want a Moonraker VI for? Would you be better off with a flat 6 or a flat 7?
My argument in favor of the Moonraker IV over the VI are as follows:
1. Smaller and lighter; easier to put up!
2. Easier to turn!
3. Performs excellent for both local (vertical) and skip
4. Does not have the bulky boom supports!
5. Mechanically superior to the VI! (same parts, less stress)
So, the VI does perform better than the IV, but not enough to overcome its shortcomings; in MY opinion. Both are great antennas!