do a google search, a large portion of iPhone owners are walking aroung with cracked screens, I see them all the time, I liked my iPhone, I had it for 4 years, I also paid $100 to replace the cracked screen about 4-5 times. I have had a Samsung Galaxy IIS for a year now. I know I have dropped it at least 10 times. The glass won't break or scratch! That reason alone is why I would never go back to iPhone. Also I like maps. And the micro SD card slot allowed me to add 32 gig to the 16 gig it came with. I can buy and swap out a battery.
Aside from all that. The user interface is just fine, plenty of apps. And I don't have to let iTunes have control over my music. iPhones are a little easier to use for old people. That is the market they are going after now. So get one if you want more face time with grandma.
looking at the two phones you mentioned , Sony Xperia Sola and the Samsung Galaxy S Advance,
the Samsung is a better phone.