I'm looking to upgrade my racket. I want to stick with the 4U series of racquets. From what I gather, the Z Force is similar to the AT800 DE, but being slightly head heavier. Is it more aerodynamic though? I'm looking for a racquet similar to the AT800 DE, but will give me the ability to smash harder and swing faster. I get the impression that the Z Force may fit my needs based on what I read, but one of the reviewers here said it's easier to play with the Voltric 80 instead of the Z Force. I would say I'm an intermediate player that plays mostly doubles. I think I'm more of an offensive minded player and have a decent smash. I also read that the Z Force is similar to the AT700, but I think I've only tried the 3U version years back so I'm not sure how it'll compare to the 4U version. Comments?