I'll admit it is not an empirical data but more likely a "perceived" data. My laptop also shipped with this card and not caused any problems on Windows 7 64-bit (it came with 8 which I immediately cleaned installed 7 to replace that tablet oriented OS). There are many factors aside from OS like you mentioned but most of them are RF oriented (e.g. antenna position inside the laptop, Bluetooth, neighboring wireless, etc.). Sometimes it appears like driver incompatibility with Windows 8/8.1/10. Rarely I see complaints with 7 but if there is, it's most likely configuration with AP and RF interference. At my work, our supplier is Lenovo and I count more than 100 laptops with 7260AC using WiFi for the 85% approx. while the rest are hardwired and not a single user complained to IT about having limited access. One thing to mention is, they all have Windows 7 Enterprise x64. That 0.01% is based on a worldwide scale, including those in the enterprise.
At home I have zero issues (no lag spikes, disconnections whatsoever) while getting 50 to 60 MB/s (aka 400 - 500 Mbps throughput out of 866.7 Mbps connection) and receiving all of my 100 Mbps internet throughout the house ALL THE TIME. This is with the use of Bluetooth mouse 24/7. On public places, I don't get limited connectivity, disconnections despite having dozens of clients connected to one AP. Speed definitely suffers but it's always connected and receiving/sending data.