I had a bumpy road with Sig, but they did take care of me pretty well.
Got a Tango4 6-24 a year ago. Arrived with a bad battery cover, which caused intermittent contact on the illuminator (flickering, extremely short battery life). Returned and fixed in about 2 weeks.
From there until about 2 weeks ago, the scope worked great for at least 1000 rounds of 300 Win. It wasn't babied, and went quite a few miles on my back. Dusty, dirty, desert shooting, etc.
3 weeks ago, the illumination turret sheared off...
Just came loose when firing. Called Sig, and they didn't have a replacement in stock, so they offered to send me an "Open Box" Whiskey 5-25. Fairly decent upgrade from the Tango4, so I told them to send it. Called Monday, Whiskey arrived Wednesday. They also expedited me a new ballistic turret.
But...The replacement scope was completely mashed! See picture below.
Needless to say, I wasn't going to accept it, and emailed the guy immediately. I mentioned I was frustrated, and he basically said "What can I do to make it right". In what I thought was a long shot, I said "Brand new Tango6 4-24". To my surprise, since the Tango6 is double the MSRP of the Tango4, he said "On its way".
In the end, I called off the Tango6, as it's just too ginormous for my use, and with the recent price drop, I figured I couldn't sell it for enough more than a Whiskey 5 to make it worth the hassle.
In summary. Sig QC seems not so great, but customer service appears top notch. Busted Tango4 and mashed Whiskey 5 means a failure at two points (manufacturing and shipping). That being said, my scope failed on Sunday, and I had a brand new, significantly nicer scope attached to my rifle by Friday night.
As for the Whiskey 5-25, it's a really nice piece of glass. Judging by the mashed one they sent me, which worked just fine, they are also pretty tough (whatever did that to the scope was a SUBSTANTIAL hit!). I'm very happy with the image quality, which is considerably better than everything else I have (Bushnell Elite 6500, Vortex HS-T, and the Tango4), and all the knobs/dials are smooth and definitive. As long as it doesn't also die in a year, I'm happy with the outcome.