Down 50% in 52 weeks, shares of Seagate Technology (STX) have nowhere to go but up. Down more than 60% in the same period, shares of memory rival Micron Technology (MU -3.23%) are looking pretty fabulously cheap as well.

At least, that's what we're hearing on Wall Street this morning, as both Seagate and Micron win new upgrades to hold from Benchmark Capital and Goldman Sachs, respectively.

Let's tackle those two in reverse order.

Why Goldman loves Micron
Perhaps the best-known stock analyst on the planet, Goldman Sachs' decision to remove its sell rating from Micron, and upgrade to neutral this morning, is the one garnering all the headlines. According to our friends over at BidnessEtc, Goldman is intrigued by the 22% slump in stock price with which Micron started off the new year.

Priced at just $10 and change today, Goldman says Micron shares now sell for less than their tangible book value of $11. That's basically how much money it would cost to rebuild Micron -- its factories, its machines, and all its other hardware -- from the ground up. As such, it's a rock-bottom valuation for what Micron shares should be worth.

And Micron is selling below it.

Accordingly, while Micron shares might not perk up immediately, with DRAM memory prices "stabilizing," Goldman doesn't see Micron falling much further than this. If it's right, anywhere sub-$11 should be a fine entry point for the stock.

Why Benchmark supports Seagate
Benchmark's decision to upgrade Seagate shares to hold is more of a mystery. We've yet to see any explanation for the upgrade reported by the mainstream media. But confirms that the upgrade did happen, and further notes that Benchmark has assigned a $32 price target on Seagate shares.

That's not quite the discount to book value that Goldman sees in Micron shares. Indeed, according to data from S&P Capital IQ, Seagate currently costs 167 times tangible book value. But it does still suggest the stock is cheap at its current price of less than $30 a stub.

Who's right?
Of the two analysts, Goldman Sachs has better name recognition than does Benchmark -- but that doesn't mean the analyst is right about Micron. In fact, according to our data here at Motley Fool CAPS, Goldman Sachs has been right on its stock picks only about 44% of the time over the decade or so we've been following its progress.

I also have real concerns about its recommendation of Micron, a company that reported $2.1 billion in "earnings" over the past year, but that generated less than $400 million in real free cash flow during the same period. Priced at nearly 33 times free cash flow today, and expected to grow its profits at barely 1% annually over the next five years, Micron stock may be cheap -- but it may also be dead money for a long time.

Benchmark, on the other hand...Well, according to our CAPS stats, Benchmark Capital has a superb record of picking winners -- better than 64% accuracy across a field of 115 stock recommendations made over the past six years. And its decision to pick Seagate, while Goldman lines up behind Micron, may also make sense.

Priced at 15 times earnings today, Seagate shares may look more expensive than Micron (which sells for less than a 6 P/E). But closer examination reveals that Seagate generated nearly $1.1 billion in positive free cash flow last year -- nearly twice its reported net income.

That gives the stock a price-to-free-cash-flow ratio of just 8.3. And while Seagate suffers from the same computer industry headwinds as Micron, and is only expected to grow earnings 4% annually over the next five years -- that's still 4 times the growth rate that analysts expect to see at Micron.

The upshot for investors
I have to admit that I find the valuation intriguing on both these stocks -- the low price-to-book value at Micron, and the cheap multiple to free cash flow at Seagate as well. On balance, though, I'm inclined to go with the better analyst on this one: If forced to make a decision between buying Micron shares today, or Seagate, I think Seagate is the safer pick.