I'm curious what you mean by "iPhone battery issue"?
You seem to be suggesting that the iPhone has horrible battery life on a grand scale. Maybe that is a reality (yes, I charge my iPhone 4 every day, too). But what you're failing to identify is that there is a certain user responsibility to ensure that a device makes the most of its resources.
Let's use a car as an example. If the driver of a car never performed regular maintenance on it, then eventually the performance and efficiency of that car will degrade.
The same logic can be applied to a phone. If I use 10 apps in a given day, and leave them all running, how will my battery perform? Some of those apps may be doing stuff that is sucking up juice. I personally experience this. If I leave the Facebook app running, goodbye battery. Even my own bank's app, goodbye battery. Proactively quitting these apps preserves battery life by a very noticeable amount.
How about Bluetooth and Wi-Fi? If I leave those turned on while I don't need them, that's like leaving my car's windshield wipers going simply because I'm too lazy to turn them off. Those wipers are wasting energy (fuel).
So, my point is, it's as much the user's responsibility to maximize battery life as it is Apple's. I mention this because I'm curious if you are proactive in managing your phone's battery in these ways?