First of all note that Xperia U and Sola are the same phones, they have minor differences. U's screen 0,2 inches smaller and it has secondary (front) camera, but you can't insert a microSD card. Sola is a bit more expensive, it doesn't have a secondary camera, but you have the option to insert an SD card. U has 4 GB of usable internal storage and Sola has 5 GB. One V's plus is that it comes with Android 4 (Ice Cream Sandwich) and HTC is known for being durable and high quality. Those two Xperia phones have planned upgrade to ICS, but Sony is kinda notorious for fucking up its updates and being slow in releasing them. If you care about the version of Android, then I wouldn't take the Samsungs, because I don't think they will get ICS, although Ace 2 might, not sure. ICS is far better than Gingerbread (Android 2.3.x). Sony (Ericssons) are one of the best phones out of box imo. It doesn't really matter which one you take if you're not a poweruser and only want to text and surf the web, all of them can do that without breaking a sweat. Of course there are many other good options, like LG Optimus L7 or Optimus Black for example, but LG isn't known for being high quality and they too regularly fuck up their firmware updates. It's best you compare the phones yourself at http://www.gsmarena.com