The Leupold VX6 is optically nicer than the Swarovski Z3 series and right on the heals of the Z6. The Z6 has very fine reticles which, so I have heard, will be or have been changed by Swarovski to an older heavier plex style. When I looked through a VX6 and Z6 side by side I felt the optics where very similar, but I could not imagine actually seeing the very fine plex on the Z6 in low light. Like I said, it might be different with current production, but it is worth checking into before buying. I ended up taking the VX6 home, even though I had the cash in my jeans for the Z6. I just could not justify spending 2.5X the money, given what I saw.
Another excellent option, and one that I was really interested in is the Leica ER series. The problem for me was that I could not find one to look through before buying. Since then my friend bought one and I can tell you that it is excellent. Mounting spacing is pretty much unmatched and optics are crystal clear. Would I pay the extra $400 over the VX6....maybe. Again it is a toss-up. The ER has more room to mount, the VX6 has a better eyebox (the best of any scope I have ever looked through) and CDS, if that is important to you. One thing you should know is that the picture Leica shows you of their IBS reticle is incorrect - it is MUCH finer and less obtrusive than shown on their website.
Wolverine has excellent prices on Schmidt & Bender scopes and I would have bought one sight unseen except for two issues. I wanted to be able to re-zero the elevation turret after adjusting it in the field and it would have been problematic as there is no numbering on the turrets, just white lines. The second issue was that the mounting size means you need close ring spacing and it simply wouldn't fit on my rifle. Wolfgang and John were both very helpful and I would happily buy a scope from them in the future.
Lastly, one that I haven't looked through but I am very curious about is the new Zeiss Victory HT 2.5-10x50. One downside is the 50mm objective lens - or that could be an upside depending on your point of view.