While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a look at particularly stock-shaking analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Ruckus Wireless (NYSE:RKUS) fell 4% this morning after Goldman Sachs downgraded the Wi-Fi products maker from buy to neutral.

So what: Along with the downgrade, analyst Simona Jankowski reiterated her price target of $19, representing just 5% worth of upside to yesterday's close. While momentum traders might be attracted to the stock's big surge since late July, Jankowski thinks that Ruckus' valuation might be a little ahead of itself at the current levels.

Now what: Goldman's call on Ruckus all boils down to price. "While we are still positive on the company's long-term trajectory and the secular growth in carrier WiFi, we see that as more fairly reflected in the stock's valuation," noted Goldman. "Since our May 17, 2013, upgrade, shares are up 36% versus the S&P 500 up 6%, driven by a solid 2Q, improving carrier spending environment, positive industry datapoints on WiFi adoption, M&A speculation, and expanding comp group multiples." With Ruckus shares up about 30% over just the past two months and trading at a forward P/E of 67 -- a massive premium to its much larger peers -- it's tough to disagree with Goldman's downgrade.

Fool contributor Brian Pacampara has no position in any stocks mentioned. The Motley Fool recommends Ruckus Wireless. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.