I still think he'll be a regular premier league scorer for years with 10-15 goals regularly per season but won't be champions league quality, mainly due to attitude , work rate and all round ability to hold up the ball as a lone front man which is how many teams use strikers these days. His finishing is top class but the rest of his games is average on the whole.
However, he's still a good player who can score regularly at this level and one we should therefore look to get a good price for. Wherever he goes, I predict for a year or two , he'll look great then will go off the boil again as he'll get bored/ fall out / get ideas above his station at his next club and so on and so on until his career drifts away the the heights he could've reached.
He's an example of a few modern young players having been spoiled rotten by doting academies ! He should have had to clean a few first teamers boots along the way to learn some humility.
When you look at 14m for a 32 yr old Defoe, then Berahino is worth at least 20m overall as he has around 10 years of goals in him in the right team (not ours and certainly not whilst Pulis is in charge). Roberts and Leko could be even better in time considering they've broken through much younger and don't look out of place whereas Bera big balls was early 20s before breaking through.