Glonass is more acurate within Russia due to the satellite orbits. Glonass is less accurate in the rest of the world. GPS is more advanced, has more satellites (32 vs. 24, hence the overall better accuracy), is more modern and up-to-date. They use the same kind of techniques with some differences in frequencies, so I don't understand where the supposed to better Glonass performance comes from.
Maybe what is misunderstood in these forums is that when GPS and Glonass are combined, like in newer chipsets for "above budget" phones, the speed and accuracy improve greatly. Because you have 56 satellites to use. So performance improvements like "first fix" and so on approve greatly due to the combination of both systems.
"first fix" for systems alone (worldwide) has always been better for GPS due to the number of satellites and the improvement to A-GPS (in almost any phone) where a wifi-signal (accuracy 20-50 meters) can be combined with 2 or more GPS signals.
I have used different devices, with and without glonass. Sure, the more satellites you see, the faster and more accurate the fix is. With glonass there is some improvement, but not too big. Tipically, your device will use maybe six GPS sats and two glonass sats.. How was that "some people experience" that you read about?