I've had my T758 since November of 2015, bought as a "factory refurbished" one with a 1-year warranty, for $700.
Early on is its life I had some stumbling with it and I recall a couple instances of needing to do a full power-down reboot. I don't recall the date but I upgraded the VM120 video to the VM130 (and my dealer threw in a BluOS kit) for 4K video with the promised discount to $200, there was also a brief period of things not working right. It do recall it coming long after I was told. A firmware update fixed that.
Another six months or so passed and the AM100 failed. I replaced it with the help of my dealer with a used one they had from a T765 update, for $50. The T758v3's were now shipping but folks like me couldn't get the new AM230 with the additional 4 channel pre-outs. NAD was apparently too busy shipping faulty ones in early T758v3's to sell me one. Another 9 months went by but I eventually got a second-generation one for the discounted cost of $530, installed. I did immediately upgrade to full Dirac Live.
At several stages the unit had trip-ups, but with dealer and NAD support it's been rock sold for at least a year now. The BluOS kit's WiFi has never failed unless my wireless router was screwing up and IT needed a reboot. That happens about every two months. For the total investment in time (3 years, 9 months) and money ($1480) that I have into this unit, I'm still way ahead of where I'd be with other units that aren't as easy for me to navigate or go obsolete in under 18 months and need replacement to stay current. I love the sound too.
It's not the unit for everyone, but I feel those who deal with the quirks are rewarded generously in sound quality and power for the money.
KEF R500, R200C, R100, R50, SVS SB2000 sub, NAD T758v3 AVR, LG UP875 4K BlueRay, Samsung UN55JU6500F 4K LED TV, KEF M500 headphones, Sony CDP-CE500 CD changer. Office: NAD M10, KEF LS50, KEF Kube 10b, Pro-Ject RPM1 TT w/ Ortofon 2M Red. Guest room: Hafler 300 L-R, KEF Reference Model 100 center, KEF iQ10 surrounds, modded M&K V-90 sub, Bluesound Vault 2.