Microsoft‘s (NASDAQ: MSFT) Windows Surface Pro and RT tablets are outselling Google (NASDAQ: GOOG) Chromebooks by roughly a three-to-one margin. Indeed Surface tablets have sold about 1.5 million units so far, compared to about 500,000 Chromebook units, according to media reports. While the Microsoft and Google-inspired devices don’t really compete head-on, the data points offer a timely reality check for mobile channel partners. Here’s why.

Surface is Microsoft’s family of touch-enabled Windows tablets. Chromebooks are web-centric notebooks — mostly low-cost devices, with the exception of Google Pixel, a high-end Chromebook that competes with Apple’s MacBook Air.

When Bloomberg estimated Surface Pro (400,000 units) and Surface RT( 1.1 million units) sales last week, the media ran wild — with most coverage suggesting the sales figures were disappointing. On the flip side, many tech media writers have been praising Chromebooks as low-cost alternatives to Windows 8 notebooks.

Among the reasons: Acer suggested that its Chromebooks were outselling Windows 8 devices. Plus, HP and Lenovo announced their Chromebook plans within a few weeks of Windows 8’s launch. Each time a new Chromebook was announced, portions of the media assumed Chromebooks were gaining more and more momentum while Windows 8 sales were likely stalled.

In Microsoft’s defense, the software giant in early 2013 stated that Windows 8 had sold more than 60 million software licenses. In stark contrast, Chromebooks have sold about 500,000 units, according to Digitimes.

For channel partners, The VAR Guy has some simple advice:

And remember: Sales figures are all relative. Don’t look at unit shipments in isolation. What do the figures mean in a broader context vs. (a) original market expectations and (b) the overall competitive market?