There are quite a few posters here who support Shahzaib Hasan to a rather unbelievable extent (the guy is a natural, they say and will be one of the best in the upcoming decade), but seem to have a lot of hatred for Fawad Alam (can't get it off the square, they chant, taking one or two scratchy innings out of a decent career to support their point). I personally have nothing against either of these guys, but here's my perspective.
Shahzaib is not hugely talented by a long shot. He's a hefty hitter who can win the occasional L/O match. That said, he isn't the mindless, talentless swatter his critics make him out to be either. He's played a couple of innings that show that, while not a world-beater yet, he has potential to be a genuinely attacking opener.
That said, I believe Fawad is a far, far better prospect. Before King Leonidos jumps me for saying this let me say why: Fawad may not win matches on his own, but he can anchor a successful run much as other unusual, gritty players like Younus and Miandad (I know, big boots and unfair comparison, but I mean he should try to look up to these types of players) do. With abundant strokeplayers in our side a second-fiddle is necessary.
Technique-wise, Fawad has a rather ugly-looking stance where he shuffles around far too much to try and nudge the ball into gaps. He used to be a pretty decent striker as well early on, but recently has seemed uncomfortable going for big hits. Shahzaib is in many ways the opposite. Where Fawad shuffles unnecessarily, Shahzaib has zilch footwork and prefers to stand and drub from the crease.
Results wise, both have had their ups and downs. So far Fawad has started out a decent career, with several hard-knuckled back-to-the-wall fifties when they've been needed. What has impressed me is that even though he was in terrible form against RSA he still managed to score useful runs at a passable clip (59 off 69, in fact, is very brisk). That says quite a bit about his mental strength. And considering he's our only Test centurion away from home, he deserves a run. Shahzaib started out decently in Twenty20s, but had a slump in England. If he continues to pillage domestic runs as he has though, he also deserves a spot.
Domestic results wise: This is a rare similarity between these two. Shahzaib has mauled runs aplenty in domestic one-days. Fawad has accumulated plenty of domestic runs as well for years.
The bottom line is, at the moment both deserve their place. Cricket is a diverse game that allows for different types of batsmen, and at the moment both Fawad and Shahzaib have started off well