I may be the ultimate fence-sitter when it comes to Amazon.com (NASDAQ:AMZN). On the one hand, I'm one of the retailer's earliest customers, and I love the premise and convenience of Internet shopping. On the other, I'm turned off by the low margins inherent in shipping physical goods, and the cutthroat competition that gives e-tailers little pricing elasticity.

That's one pretty big fence I'm sitting on. I can praise Amazon for succeeding in profitable online retailing as smaller upstarts like Overstock.com (NASDAQ:OSTK) and RedEnvelope (NASDAQ:REDE) struggle to turn the corner. I just don't know whether the company will ever produce the margins some investors expect -- or deserve its current value up there with the dot-com elite.

Amazon has started to make inroads in digital delivery, a trend I'm definitely watching. But for now, sitting on the fence isn't too bad -- it gives me a great view of this week's bout. Is Amazon.com a winner or a loser? Not all Fools agree when it comes to this popular Motley Fool Stock Advisor newsletter service pick. Alyce Lomax is bullish on the company's prospects, while Chuck Saletta feels the valuation is out of whack relative to more conventional retailers.

Does Amazon.com belong in your shopping cart? That's what this week's Duel is all about.

Duel on!

RedEnvelope is a former Motley Fool Hidden Gems pick, while Overstock.com was a former Rule Breakers selection.