First, everyone's "real world use" means next to nothing to others, because one person's "real world" may be 100% web, well another's maybe 3 days of standby with occasional call. I charge my phone every 2-3 days, use it for email primarily, i handle battery carefully and my battery drop 0-1% over 8 hr standby, tell me which "real-world use review" help me? If there isn't a clear definition of "real-world use", how exactly will any assessment be made?
These AC, AA verge, etc, reviews, basically saying absolutely nothing.
By relying on battery rundown test, GSMarena's results are great because:
1) it gives objective comparison between smartphones. If it says smartphone 1 is 50% better than smartphone 2, it is just that. Especially If I have smartphone 2 already, I would know exactly what I will get, with my own usage.
2) it offers individual personalized rating because on your own usage. You use 2 hr web a day instead 1? you do 5 hr video instead of 2? sure, adjust the slider for yourself.
3) it's test results matches my own battery calibration tests.