In the smartphone wars it’s often very hard to tell who’s winning and who’s losing. Often it depends very much on what metric you use. If you go by total market share, Android is the clear winner. If you go by units sold in the last quarter, it’s the iPhone by a sizable margin.

Millennial Media’s Mobile Mix report adds another angle to the debate by gathering data on impressions from mobile ads. Millennial Media is a mobile advertising platform company that specializes in mobile apps and the mobile web. The data collected from mobile device impressions on their ads provides a pretty good clue as to which devices are the most popular. Their data reveals some interesting trends in the mobile market.

In terms of overall market share, the Mobile Mix data confirms what most similar reports have shown: the Android platform is the top mobile operating system overall. According to the report, Android makes up 49% of the smartphone market, while the iOS has 33%. BlackBerry is in a distant third with 13%.

The fact that Android is the top OS, though, doesn’t mean that an Android phone is the top smartphone. In fact, the iPhone is the top smartphone by a considerable margin. That shouldn’t come as a surprise, however. The Android platform’s 49% market share is divided among a plethora of smartphones, while Apple’s iPhone has the iOS portion of the market all to itself (well, along with the iPod Touch and the iPad, of course).

Where this data gets interesting is when you start trying to figure out who the top smartphone maker is. You may recall a story we did earlier this month wherein we reported that Samsung is the world’s top smartphone vendor. That report was based on data that showed that Samsung shipped just over seven million more smartphones last quarter than Apple (42.2 million for Samsung, 35.1 million for Apple). The Mobile Mix data, though, paints a slightly different picture. While Samsung may have sold more smartphones than Apple overall, Apple still maintains the top spot based on the the report’s data.

Given the fact that Millennial Media is works with mobile app developers, as well as with mobile website developers, you might expect the report to spend a little time dealing with data related to mobile apps. In that, you would not be disappointed. The report ranks the top ten categories of mobile apps across all platforms. Not surprisingly, the top mobile app category is games. In second is music and entertainment, followed by social media.

The report also had some interesting insights into the current tablet market, as well as some predictions about the tablet market in the coming years. The data showed that 20% of Millennial Media’s impressions in the first quarter of 2012 came from “non-phone connected devices,” i.e., tablets. Of those tablets, the iPad held a significant lead over its competitors as the most popular tablet overall. The other tablets in the top five were the Samsung Galaxy Tab, the Amazon Kindle Fire, the Motorola Xoom, and the BlackBerry PlayBook. Of those five tablets, the top three were also on the list of the top 20 overall mobile devices, meaning that each beat out at least a few smartphones in terms of popularity (and it’s likely that the iPad beat out quite a lot of smartphones).

The report also used current sales data from the tablet market to project what that market will look like over the next several years, and the results are pretty interesting. Tablet sales are expected to grow by 54% in 2012, reaching 106 million units sold. Based on that, the Mobile Mix report predicts that by 2016 the tablet market will see almost 100% growth over the next 4 years, reaching 198 million units by 2016.

The Mobile Mix report may not settle the question of which smartphone (or smartphone platform) is best. It may not even answer the question of which is winning the great smartphone arms race. Nevertheless it does provide some important insights into the current state of the market. For more information, you can check out Millennial Media’s research page here.