I've been trying out an Xperia X10 mini which my friend bought last month. To put my review short, its a very good phone. The timescape ui is awesome and the capacitive touch screen makes it really crisp to use. Its using Android 1.6, and I heard from him that Sony will be providing an upgrade soon.
Comparing with the Samsung, I guess, the Galaxy would be using the touchwiz UI on top of Android. But looking at the specs, these are my thoughts.
The Samsung as usual has got a 3.2 inch screen while sony is little off with a smaller 2.55 one. But the resolution is same, which means images in the Sony will be much sharper. Unless you are a regular movie viewer in mobile, this isn't going to make much of a difference.
Coming to the processor, samsung has a 800 MHz one while sony is little low with 600 Mhz.
The Xperia has got a 5 MP camera and 30 fps VGA video recording while the samsung is lagging way behind with 3.15 MP and 15 fps cif. Who needs that when the era of HD video recording and playback is becoming the new trend.
I have had really bad experiences with Samsung mobile cameras. Although with autofocus, some clarity is achieved, but the images are so dark and washed out as if taken from a VGA camera.
In the battery segment, the Xperia has a concealed battery. You can't take it out just by opening the back cover. I couldn't find its specs anywhere, until recently GSMArena recently reported it as 950 mAH compared to the huge 1500 mAH of the samsung. But for a smaller screen and a tiny phone, its Ok. In the X10, the battery lasts max a day and half on full charge. It may be a problem to you if you are looking for longer battery life. But the galaxy with its huge battery still won't last any longer as its screen is bigger and Samsung touchscreen fones are seen to have very low battery backup. The X10 mini has got USB+Normal charging through the same cable, as seen in apple products.
The sound quality is same as was in older SE models.
There is no equalizer in the media player provided with it, unless you install some other media apps. Bluetooth doesn't have OBEX support(as far as I found out), meaning you can't use your pc to browse the contents of the phone through bluetooth.
Although, not being a fan of SE phones, my recommendation still would be to go with the X10 which is rich with features, the main being 5MP cam with VGA recording, and the sleek new looks. Its a really cute phone staying right inside your palm.
It has got interchangeable back covers too.
