The last two years or so have been a great time to own foreign telecom stocks . unless you're talking about Russia's Mobile TeleSystems (NYSE:MBT), that is. Whether it's worries about competition and falling per-user revenue, worries about regulation and government policies, or worries about management execution, there have been plenty of reasons floated for keeping a safe distance from this stock.

And judging by fourth-quarter earnings, it would seem that the skeptics had something of a point. Revenue, EBITDA, and net income were all up by amounts that would ordinarily seem quite satisfactory, but they were all a bit shy of analyst estimations. Not big misses, mind you, but enough for the skeptics to go "Ah hah! I told you so!"

Looking at some of the various statistics that Mobile TeleSystems provided, the one that jumps out the most is the ongoing sharp drop in average revenue per user. ARPU in Russia fell 35% and in the Ukraine fell 27% from last year, which was better than the year-over-year drop seen in the third quarter, but not by much.

Though some people will undoubtedly read a lot into management's apparent admission that business will be getting tougher, I'm not exactly sure why anyone would really be surprised by this. After all, how many competitive markets can you name where conditions are getting easier?

It's clear to me, though, that Mobile TeleSystems will have to continue to be aggressive and opportunistic in seeking out new markets. According to data provided by the company, mobile penetration jumped to 87% from 51% in Russia this year, and to 64% from 29% in the Ukraine. The trick, though, is that many of the underpenetrated markets near Russia aren't particularly wealthy, so you can wonder what the future holds for the company's returns on new capital investments in these regions.

The good news here is that Mobile TeleSystems no longer looks as expensive as it once did, and I believe it's still better-run than rival VimpelCom (NYSE:VIP). With so many options to choose from, though, ranging from well-established companies like Vodafone (NYSE:VOD), NTTDoCoMo (NYSE:DCM), and Telecom New Zealand (NYSE:NZT) to riskier ideas like Philippine Long Distance (NYSE:PHI), Fools should do plenty of due diligence on the other options out there before settling on one provider.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).