Well, when I'm traveling which is a lot (I live in Paris but I'm in China at the moment), I tend to use a lots of apps to guide myself : 2 dictionaries at least, Baidu Maps or Google Maps, WeChat, Whatsapp, à VPN (must have in China) and the Web browser (I use Chrome), the Mi2S tends to overheat and the battery consumption seems higher than when I just bought it one year ago. Dunno if the hardware is getting older, I often use the battery saving power mode but it's not always practical. For example, you're outdoor in China during summer time, it's very very sunny, so you're really need your max brightness which the power saving mode won't provide.
With apps demanding more and more resources like storage or processing speed (Chrome is over 200 MB), the limited app storage and the overheating (I'm using a 3000 mAh battery) are really issues on a daily basis for me.
I might not upgrade to the Mi4 since I want 4G connectivity. It's not like the coverage is 'early as good as it should be, like in Paris (France), but in a year, it might be good enough to expect to have a permanent 4G connectivity in big cities.
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