Well, My skills are not as good as I hoped, but I did come away with an extremely clean bow for $700. Bought the Heli-m, shoots great, very pleased with it.
Congrats on the purchase, good looking bow and as long as you are happy with it that is all that matters.
Of all the Mathews I've ever owned... z7xtreme, helium, Creed, Chill, HTR, Halon, Halon 32... The Helium was my least favorite. I shot it fine but absolutely hated the bow. My vote is for the Magnum, hands down.
I would go with the Z7 Magnum. I have one as my secondary bow that I will always have. It is still faster than any Mathews bow out there set to 70 lbs. Like Justin said, at that price it gives you more money for accessories to customize it the way you want to.
Little late on the draw dubs, already bought it, now it's time to drop some chickens. I really wanted that magnum, but it didn't look like it was coming from a guy that was invested into the bow. I feel pretty good about the heli-m, shoots well, small learning curve going from PSE to Mathews, but definitely like it.
I'm still shooting a LX...its a tack driver. May not have all the "new" bells and whistles, be as light, shows a little wear, but it does just fine.