Apple (NASDAQ:AAPL) is popular again. Apple stock closed above $600 for the first time since late 2012 yesterday, naturally notching a new 52-week high. The gains were extended during the trading day this morning before slipping back below the $600 milestone. You have to go all the way back to October 2012 -- 19 months ago -- to find the last time that Apple stock has traded as high as it did this morning.

Bulls will argue that the pop is long overdue. After a slump through most of 2013, where earnings and profit margins buckled, Apple responded with a blowout quarter two weeks ago. Margins widened and profitability improved. Apple's profit of $11.62 a share was well ahead of the $10.09 a share that it earned a year earlier and the $10.18 that analysts were targeting.

However, lost in the post-report rally is that Apple is still being challenged. Net sales climbed a mere 4.6% worldwide, and it was a more humbling 1.8% uptick in the Americas. That's barely enough to stay ahead of inflation's 1.5% rate for the 12 months through the end of March.

Apple is doing well in Japan. It's the only market where the iPhone commands a greater share of the smartphone market than in the U.S., and sales also grew nicely in Greater China. However, can we really hold up 1.8% growth in the Americas as a success?

The iPhone is doing well. Macs are holding their own in an otherwise-stagnant PC market. However, the double-digit decline in iPads is problematic. Apple reassured investors that the iPad plunge wasn't as bad as it looked on paper. The 13% drop in sales and 16% decline in units wasn't indicative of the actual sell-through to consumers. As Apple explained during its call, it may have sold 16.4 million iPads to retailers, but folks actually purchased 17.5 million units. Its channel inventory decreased by 1.1 million units to a more normal level. That certainly takes some of the sting out of the iPad shortfall, but it also suggests that the holiday quarter -- Apple's fiscal first quarter -- wasn't as hot as the increase in iPads suggests if retailers had excess inventory to taper new orders. Either way, it was still a year-over-year decline.

The market's cheering Apple's decision to split its shares 7-for-1 early next month, but that's clearly a zero-sum game. It's cheering Apple's aggressive share buybacks, but all that means is that the 15% growth in earnings per share this past quarter was actually just a 7% step up in net income. Outside of the 17% pop in iPhones, is there really any other reason to get excited about Apple?

The answer -- despite the occasionally negative tone of this article -- is in the affirmative. Apple at $600 isn't outrageous. It's less than 14 times this year's earnings forecast and less than 13 times next year's target. That may not have seemed like a bargain when margins, earnings, and even sales were going south, but it's a different ballgame now. Apple is back in "trounce mode" and that's before it introduces one of the breakthrough products in new categories that it has been promising for months. May might prove to be a good month for Apple shareholders ahead of next month's stock split, but the real fireworks await later this year as the iPhone 6 and forays into new realms bear fruit.

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Rick Munarriz has no position in any stocks mentioned. The Motley Fool recommends and owns shares of Apple. 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.