The matches I was watching this weekend seemed to show the Gulbis forehand landing short in the service box quite often.
Sure it worked for him and he won a title, but that forehand will be exposed for the weakness it is when he meets one of the big boys.
A hard hitter like Berdych or Tsonga will create real problems for the Gulbis forehand as his setup and motion require too much time.
A solid baseliner that can retrieve all day like Ferrer, Djokovic, and Nadal will get hit to the Gulbis forehand until it breaks down. So much motion in it that its going to break first over the players with better technique.
Racquet: Wilson PS97 String: Prince syn gut @55lbs in mains, ISOSPEED Baseline Control 16 @50lbs in crosses