Best 5.25'' speaker?

You might be disappointed in any 5.25" speaker without a subwoofer if you listen to rap and want bass.  They simply can't do a good job with it.  Those commissioned sales persons might not be lying to you.  There isn't one "best" speaker for every one.  It depends on your ear, your budget, your music, and how you plan to power them.  Look at brands like the MB Quart RCE series, Focal Access, Infinity, Memphis, Diamond, Eclipse, etc.  and you really need to demo them and make your own call.   Bring your music into the store and do a/b tests on similar equipment to what you run.  (i.e. if you're going to be listening off a blaupunkt head unit then demo them solely off a similar head unit in the store, NOT an amped speaker - unless of course you plan to get an amp in the near future).