I own the Super X2 and Super X3. Both guns are very reliable if you keep them clean. Neither model can go as long without cleaning and function properly as my Beretta Xtrema2 or my Remington Versamax. However I really like the feel of the Super X3, in fact I like it so much I picked up another one on closeout since they are discontinuing the Super X3. I'm sure the X4 is fine, it's less expensive. You get what you pay for. My vote would be for the X3. A lot of places have been selling them for very good closeout prices lately. Good luck in whatever you choose!