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." So you might think we'd be the last people to give virtual ink to such "news." And we would be -- if that were all we were doing.

But 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. To help, we've enlisted Motley Fool CAPS, our tool for rating stocks and analysts alike. With CAPS, we'll be tracking the long-term performance of Wall Street's best and brightest -- and worst and sorriest, too.

And speaking of the best ...
I usually speak of "the best" in a general, forgiving sense -- the same sense, I suspect, that convinces the Wall Street bankers that they are indeed better stock pickers than the rest of us are (despite all evidence to the contrary). Every once in a while, though, one of the firms that truly deserves the title "Wall Street's Best" comes along and publishes a stock recommendation. That happened this week.

Yesterday, investment banker extraordinaire Jefferies initiated coverage of one of our own favorite stocks at Motley Fool Stock Advisor -- chip maker Silicon Labs (NASDAQ:SLAB). Calling the stock a "rare opportunity ... that combines sustainable product cycle-like revenue growth (15 percent to 20 percent year-over-year) with the margin profile (60 percent to 62 percent) and product/customer diversification of an analog company" Jefferies tagged Silabs an out-and-out "buy."

So what?
That's a fair question. When you consider that only one single "professional" analyst currently ranks in the top 1% of players on CAPS, investors can be forgiven for taking a jaded view of the supposed expertise of the experts. But not everyone can be No. 1, and within the field of professional stock pickers at least, Jefferies' record compares pretty well to those of its peers. If you absolutely must follow the advice of a professional, I think you could do a lot worse than listening to one that places seventh in a field of 122, boasts a CAPS ratings of 95.92, and calls 54% of its stock guesses correctly.

We've been tracking the firm for well over a year now, and the firm is looking pretty good, having picked three near-triples:

Company

Jefferies Said:

CAPS Says:

Jefferies' Pick
Beating S&P by:

Excel Maritime
(NYSE:EXM)

Outperform

****

196 points

Halozyme Therapeutics
(NASDAQ:HALO)

Outperform

***

196 points

DryShips (NASDAQ:DRYS)

Outperform

*

162 points

But not a single stock that has underperformed the market by more than double digits, its three worst active picks being, respectively:

Company

Jefferies Said:

CAPS Says:

Jefferies' Pick
Lagging S&P by:

Staar Surgical
(NASDAQ:STAA)

Outperform

*

70 points

Sunesis Pharma

Outperform

*

55 points

Molecular Insight
(NASDAQ:MIPI)

Outperform

*

56 points

Foolish takeaway
With an accuracy record of just 54%, you might not ordinarily expect to see Jefferies on a list of the "best" of anything, much less stock-picking. But the company has a record of picking rocket stocks that transform a near-average ability to pick companies that outperform the averages into a superb record of picking superb winners.

Reviewing the numbers at Silabs, I can't help but think many investors will think Jefferies has done it again with this one. The stock carries a mere 13 P/E, yet analysts expect it to grow its "E" at nearly 19% per year for the next five years.

Personally, though, I'm a bit skeptical of that P-divided-by-E-equals-buy thinking. The whole idea behind fabless semiconductor makers like Silabs, after all, is that their "asset-lite" business model should be able to churn out great gobs of cash, with little capex to impede the flow. Yet at Silabs, trailing-12-month free cash flow is an anemic $19.9 million -- less than 70% of what the firm reports as net earnings under GAAP. The resulting price-to-free cash flow ratio of 111 makes me feel a little queasy.

With all due respect to Jefferies, therefore, and to the good folks at Motley Fool Stock Advisor who have guided investors to an average of 28% returns on their three recommendations of Silicon Labs over the years, I'm going to pass on this one.

What's that? Two opinions on the stock not enough for you? Then check out what the current score leader on Silicon Labs has to say about the company. And while you're at it, pick up a free trial to Stock Advisor. Maybe there's good reason to buy Silabs today, despite my misgivings. You won't know until you've read the write-up. And since free trials are, well, free, you don't really have anything to lose.

Fool contributor Rich Smith does not own shares of any company named above. You can find him on CAPS, publicly pontificating under the handle TMFDitty, where he's currently ranked No. 415 out of nearly 65,000 rated players. The Fool has a disclosure policy.