I am surprised that Roma sold him, because there are rumors of them selling Osvaldo as well. May be this means Osvaldo is staying. Their other striking options are limited as well.
I thought he was very useful for Roma, runs a lot, works a lot, and is decent. The price is about right for such a young player, may be a 1-2 millions too high, considering Barca are willing to sell Afellay for 6-8 million euros. But in English market, it's still a good price.
What I would say is that don't expect Borini to be some superb player right away. I watched plenty of Roma matches (thanks to Luis Enrique managing them) last season, and whilst I thought Borini was one of their better options in attack, he wasn't a magician. He is a hardworking, decent player. Expecting something more may result in frustration. The fact that he couldn't make it into Italian NT squad for Euros should tell that he is still raw, and has some way to go. Competition in current Italian NT is nothing like in the days of Del Piero and Vieri, so if the lad still cannot get in the squad, there's a reason for it.