It's highly unlikely that a soundbar would beat a piece-meal system in terms of sound quality or surround sound. Soundbars are a middle ground solution of better sound and simple set up. I'd strongly recommend an actual surround sound system if you've got the budget for it. Seems like you've got a nice set up going... the only thing I'd be weary of is the subwoofer. I never cared for the PSW subwoofers, they're too boomy/muddy.
I know some people say soundbars offer great surround but I never thought any of them came close replicating surround sound... they kinda just, filled the room with sound (ie, it was the same 'loudness' everywhere in the room). I've had the Samsung HW-FM45C and HW-F355, JBL SB150 and the H/K SB16 and out of all of those, I only kept the SB16, which sounds amazing, and the HW-FM45C for my bedroom. Granted, none of those are high end soundbars but still, none of them come close to replicating my surround sound system.