Sony is celebrating the shipment of the 50 millionth PlayStation 3. But sales of its Move motion control system are slower than that of Microsoft’s Kinect.

The company says it reached the figure on March 29. Given that (according to the Telegraph) shipments totaled 3.5 million in 2006, 9.1 million in 2007, 10.7 million in 2008 and 13 million in 2009, that makes 14.3 million sales in the past 15 months. At first glance that looks like a slight decline, but take into account Christmas and sales are still holding up.

By way of context, the 50 million sales means the PS3 and XBox 360 (which claimed the landmark in January) are almost neck and neck for fifth and sixth slot for the all time sales chart for consoles (not including handheld devices), with the PS2, PlayStation, Wii and NES ranking one through four respectively.

The PlayStation, PS2, and PS3 also becomes the first home console line to top 300 million sales: Nintendo’s suite from the NES through to the Wii is at around 250 million. Include handheld consoles, however, and Nintendo takes a 595 million to 370 million lead.

In other Sony stats, there are now 75 million people registered on PlayStation Network. Taking into account the number of people buying used consoles, that seems relatively low and suggests one-user households (or at least homes where only one person regularly games online) are by far the norm.

There’s also been a total of 480 million games sold for the console, averaging just under 10 per person. Given that this won’t include rentals or second-hand games, I’d consider that an impressive figure: the median length of ownership is right around two years, so that’s an average of each player buying a game every 10 weeks.

The company has also announced shipments of eight million Move controllers. That’s two million behind the Kinect system, even though the latter is considerably more expensive. The usual disclaimers about shipments vs. sales applies, though the head-to-head comparisons seem fair: as of the beginning of 2011, about 80% of each company’s motion control shipments had been sold to consumers.