The main problem i have with anything running a mobile OS is browsing.
Both android and IOS are completely useless when it comes to anything slightly out of the norm and seem to struggle hugely with flash/java.
Android crashes out a lot, Firefox seems to be the best at handling most stuff but the stock browser and chrome are just terrible.
IOS is even worse, it won't crash but that's because it just flat out refuses to load flash.
The other serious issue is processing power and RAM, waiting any longer than a second for a page to load just frustrates me, they are improving over time but will always lack the brute force of a desktop.
If you want to do anything other than check Facebook and play angry birds then do yourself a favor and buy a real laptop or desktop!