How far do you plan on shooting? How much extreme-low light shooting are you going to be doing?
I've a Conquest 4.5-14x50. It's great for both of these things, thought it doesn't have any windage holds and I suck at wind calculation/holding, I have shot out to 400yd with it. Killed animals out to 300.
Friend has the Swaro Z5. It's barely brighter than my Conquest, if it is; I haven't seen the difference. Doesn't really have turret options, though, and the Conquest and HD5 do.
One downside of the Conquest line is that they are in .25 INCH clicks, not .25 MOA clicks. That screws your math past 300yd (from what I understand whilst asking Chad about it), and you have to go IPHY (inches per hundred yards) instead of MOA. I personally liked MOA better than IPHY, and MILs are easier, from what I understand.
I wouldn't cut short the TANGO4. Saw a gentleman at the range shooting lights-out with it at 200yd and it wasn't his gun, but he liked the glass. Burris XTR II has a lot of attention and a THF following; I looked through it and darn is it clear...also fatter than a banana
If you're shooting within 300yd then go Zeiss. If you want to reach out to 5, maybe further, I'd say go XTRII.