...if by "just like" you mean, "not much at all".
John Scalzi tasted the new "Holiday Spice Pepsi" recently, and he was underwhelmed. In truth, nearly everybody I've spoken to about this stuff has been similarly underwhelmed -- but that means nothing to me, for as I indicated a couple of weeks ago, I love the stuff. It's a real problem for me, because I've been largely able to banish sugared colas from my drinking regimen over the last couple of years (sugared coffee, on the other hand, isn't going anywhere), and this stuff is putting a huge dent in my ability to remain contented with good old Diet Pepsi. In my favor, though, is the likelihood that as a seasonal product, Pepsi Holiday Spice will be vanishing from the shelves sometime in the next month or so.
(Note to self: By ten cases of Pepsi Holiday Spice.)
I don't exactly recall what Pepsi-Clear tasted like, but I don't recall it having any hint of "spice" about it -- I remember it tasting like a cola that had something missing (beyond the obvious caramel coloring). It reminded me of those weird-named colas you used to find at no-frills supermarkets, like Faygo (whose cola was nauseating, but whose "Redpop" and "Frosh" flavors were mildly pleasing) or Fanta or Shasta (actually, I haven't had Shasta since I was six, so I may be treading on unfairness here). Nothing in Pepsi Holiday Spice's flavor made me think of Pepsi Clear; I suspect that what John's remembering is the last ill-conceived variation on its formula Pepsi cooked up.