There's ALOT of Glock fans in this forum so you're probably gonna get a biased answer. My take on it is that the Glock has a track record for dependability and for being nearly indestructible. They're also fairly accurate by comparison. And last, they have a really high magazine capacity. The down sides is that the G26 I tried once I put it back as fast as I picked it up. The darn thing was really really top heavy. The center of gravity of that particular pistol was a decent amount higher than it should have been for stability sake. Also, the Glock trigger is famous for causing more than one person to scratch their heads with a bewildered look on their face. Mind you, it's no where near as bad as a Taurus trigger or a Ruger but it does take a little getting used to. Also, I personally think Glocks are really ucking fugly! There are alot of good pistols out there that perform just as good if not better than a Glock so don't just buy the Glock because all your friends have one. The PX4 Storm is a really good pistol too. I personally think it's balanced better than the Glock. I also think it looks better (but that's beside the point). The PX4 Storm may not have quite the following as the Glock, nor does it have the reputation of the Glock but is is still a really nice pistol. The down sides of the PX4 Storm is that many people with small(er) hands say its too wide. Also, the spring for the safety lever is WAY TOO STIFF for the first 500 times you use it so you might want to buy a weaker spring for it and stick it in there first thing when it arrives. Also, it has accuracy to compete with the Glock, as long as you can do your part that is.
In summary, both pistols are really good pistols and you WILL NOT be dissapointed with either one. Go to the store, pick up the one, then pick up the other, look at the price tags and make your decision based on your first gut reaction. All in all it's kinda like asking "So, do you want the red apple or the green apple?" They're equally good, just try them, pick them up and hold them and decide for yourself, neither one will let you down.