I recently blogged about the Samsung Galaxy SII vs. the iPhone 4s. I ended up choosing the Samsung phone and have been using it for almost a month now. Enough time to share my impressions.
The Good: The Samsung has a great screen - much better than the iPhone 3GS it replaced. From in-store comparison with the iPhone 4S, I'd judge it better than it too. Also, the physical dimensions of both the screen and the phone itself are, in my opinion, better than the iPhone. Another great new (for me at least) feature is the Google Map/Navigation. I can't emphasize enough how convenient it is to be able to enter an address or simply a point of interest via natural voice instead of fumbling with a keyboard. And Google Maps' ability to understand is pretty amazing - it rarely makes a mistake when I ask for an address. Siri it is not, but very useful, nonetheless.
At first I didn't like Android's separation between application folder and the home screens. But now I can see the usefulness of being able to put all the "important" stuff I use every day on the home screens...and everything else in the applications bucket.
Another nice feature is the Notification area. I use it all the time. Apple's iOS 5 has Notifications now too, but I have no experience with it there - the Android one is done well.
The Bad: The user interface is just not as intuitive as the iPhone's. I don't know what it is - perhaps it's all the junk apps the vendor and/or phone operator pre-installs - or perhaps it's the duplicate apps that do the same or similar things (e.g. "gmail" app and a "mail" app; "AT&T Navigation vs. Google Navigation). Perhaps it's the lack of physical buttons for menu/home/back/search - forcing you into trial-and-error when not looking or when in the dark (how brain-dead is it anyway that those keys light up *AFTER* you press them). By comparison, the iPhone has a physical Home button that your thumb can find by "feel" and, thus, allows for at least some rudimentary navigation without looking.
Some of the built-in applications (e.g. the alarm clock), although often more feature rich than the iPhone's equivalent, are of questionable quality and/or usability. For instance, I use the alarm clock every day. But a couple times, when I had to change my normal "wakeup time", have found myself oversleeping because I somehow managed (fat fingered or bug in software?) to change the hour instead of the minutes. That never happened to me on the iPhone.
Or take the email app. In the default view, you see your inbox arranged reverse chronologically and separated by days. That's good. But deleting a message without viewing it first involves 4 touches (Menu->Delete->Check the message->"Delete")....vs. the iPhone's swipe->"Delete". Placement of on-screen buttons is also not very good. In the mail client, "Compose", "Reply", and "Trash" are all near the top-right of the phone, making them hard to reach with the thumb on a tall phone like the Galaxy.
The Ugly: The battery life of the Galaxy S II is just horrible. I think much of it is due to the apps in Android not being well designed - many seem to communicate with servers way too frequently (to fetch news updates, ads, etc.) After de-installing various apps (e.g. the "Engadget" app; the "GO" keyboard; Facebook) and setting others to check for notifications much less frequently (e.g. gmail) and by turning off wi-fi or GPS when I'm not using it, I can get through a whole day without sucking the battery dry....but what's the point of having a "Smart" phone when you have to make it dumb to make it last through a day?
The keyboards on the Samsung all suck. It's kind of funny - the iPhone had one keyboard and I hardly ever made a mistake on it. The Galaxy S II gives you a choice of THREE built-in keyboards...and I can't even enter a simple google search without accidentally entering a period instead of the letter 'n'. Maybe it's the dimensions of the phone - it's much taller and perhaps a little narrower than the iPhone. The keyboard letters seem squished. There are several third-party keyboards available for Android (I guess they sprouted because there's a definite market?) and I found one that was pretty decent - the "Go" keyboard....but seemed to be a contributor to my battery woes (I suspect it was phoning "home" for unknown reasons), so I uninstalled it again. I now live with the crappy keyboards as best I can (I try to use voice more), but it's not easy/fun.
Finally, there are some apps that are just not available on Android (yet). The two I hate not having are: (1) Bloomberg Radio+ and (2) the Optimum Online app. The latter one actually exists for Android, but it's a piece of crap that requires you to have DVR before it does *anything* (meanwhile, the iPhone version not only gives you a channel guide (that can act as a remote for your cable box!), but also lets you view live TV).
The Verdict: While the Galaxy is a physically beautiful phone with an awesome screen, I wish I had gotten the iPhone 4S. Since I didn't, my hopes are now pinned on Ice Cream Sandwich becoming available on the Galaxy SII which will, hopefully, address some of issues I mentioned.