For functionality absolutely not, as many people find the combination of angles and lengths and looks to work better than a paired set. That being said, normally it does look nicer if it is with the stem/hb they are designed for.

Pretty sure my specialized is all specialized stuff but I just put Easton EA70 bars and stem on my giant this past winter. I am glad I went with the set as it does look nicer than anything else I could have picked out.