At The Motley Fool, we poke plenty of fun at Wall Street analysts and their endless cycle of upgrades, downgrades, and "initiating coverage at neutral." While the pinstripe-and-wingtip crowd is entitled to its opinions, we've got some pretty sharp stock pickers down here on Main Street, too. (And we're not always impressed with how Wall Street does its job.)

Given this, perhaps we shouldn't be giving virtual ink to "news" of analyst upgrades and downgrades. And we wouldn't -- if that were all we were doing. Fortunately, in "This Just In," we don't simply tell you what the analysts said. We also show you whether they know what they're talking about.

Today, we're going to take a look at three high-profile ratings moves on Wall Street: a price target boost for Smith & Wesson (Nasdaq: SWHC), a buy rating for Rentech (NYSE: RTK), and on the downside, a steep downgrade for Medtronic (NYSE: MDT). Let's dive right in.

Smith & Wesson shoots, scores
Local gunsmith Smith & Wesson shot right out of the gate this morning, its shares rising 20% in a matter of hours in the wake of a fiscal third-quarter earnings beat. The company edged out consensus estimates for revenues, but where S&W really shined was on profits -- which came in at twice the levels Wall Street was expecting.

With the shares now exceeding the price target Northland Securities had previously set for them, the analyst wasted no time in raising its sights on a new price target: $8. But if you ask me, that looks a wee bit optimistic.

Why? Well, consider that at today's price, the shares are already trading north of 90 times earnings -- a pretty rich multiple for a company that most analysts expect will post only 15% long-term profits gains over the next five years. (For comparison, rival Sturm, Ruger (NYSE: RGR) shares fetch only 21 times earnings, and are enjoying zero "pin action" off the S&W earnings beat.) Furthermore, the boost that S&W enjoyed four years ago, when NRA President Wayne LaPierre was warning people to buy firearms quick before then-candidate Obama could take away our guns, is looking less likely to repeat four years into the Obama presidency.

I don't know about you, but my gun safe is still looking well-stocked, and unconfiscated. I'm in no hurry to buy more firearms... and at this price, in no hurry to buy S&W stock, either.

Rentech running strong
Two months ago, I told you about a pair of companies operating in the twin industries of fertilizer and renewable energy (!), and how Brean Murray thought both were pretty good bargains. This morning, a second analyst agreed.

Initiating coverage of both Rentech and subsidiary Rentech Nitrogen Partners (NYSE: RNF), vowel-challenged stockbroker Feltl & Co. announced it likes both stocks a lot, but prefers to own the parent company Rentech -- giving that stock a "strong buy" rating, versus the mere "buy" assigned to R-N. Interestingly, Rentech management seems to agree. Just a few weeks back, the company announced that it intends to spend $25 million buying back its own shares.

But as I argued earlier this week, management is actually buying the wrong Rentech this time -- and Feltl is endorsing the wrong ticker, as well. Unprofitable and burning cash as it attempts to produce a viable synthetic fuel product, parent company Rentech is actually a much less valuable commodity than its mundane, fertilizer-producing offspring. Where the former is unprofitable and burning cash, the latter is earning profits and churning out cash by the barrel-load. If you're interested in investing in Rentech at all, I'd urge you to take a good hard look at the subsidiary before tapping the "buy" button. It's outperformed since I recommended it, and I think it'll keep outperforming from this point forward.

Medtronic to the ER -- stat!
Finally, and with my apologies for ending on a down note: Medtronic, which got walloped upside the head with a downgrade from Argus this morning. So far, Medtronic has reported year-over-year declines in profits in two of its past four quarters , and according to Argus, such weakness is likely to continue. The analyst warns that sales growth is slowing in three of Medtronic's biggest businesses, and says investors are best advised to sell the shares now, before things get any worse.

And Argus may well be right. Mind you, at less than 12 times earnings, Medtronic stock isn't exactly expensive right now. It's entirely possible that the bad news Argus mentions is already priced into the stock. Even so, though, analysts are currently projecting just 6% annual long-term earnings growth at Medtronic. That may not be fast enough to support even a 12 times multiple on the stock -- no, not even with Medtronic paying a 2.6% dividend.

Foolish takeaway
Medtronic stock may not be the priciest or riskiest company out there on the markets today. But one thing's for certain: At this valuation, there are better places you can put your money. In fact, you can read about one such stock in the Fool's new report: "The Motley Fool's Top Stock for 2012." Download it for free today -- but click quick. This report won't be available for long.

Whose advice should you take -- mine, or that of "professional" analysts like Northland, Feltl, and Argus? Check out my track record on Motley Fool CAPS, and compare it to theirs. Decide for yourself whom to believe.