Android has been given a fair bit of stick recently for being very malware friendly. While the competition, including Steve Ballmer, are clearly rather subjective a recent report from F-Secure has a lot more credibility.
Their most recent report for Q3 2012 reveals that there were 51,000 instances of malware, compared to a mere 5000 in the previous quarter. Now here's the truth, of the 51,447 malware examples discovered by F-Secure only 146 came from the Google Play Store. That's a relatively minor 0.28%.
Of the 51,447 examples, many of them weren't actually all that dangerous. 55.2% were malicious while the remaining 44.8% were only labelled as risky.
It is worth pointing out that many users do occasionally resort to sideloading applications and as these are not monitored by Google they are much more prone to malware. On a positive note, from Android 4.2 Jelly Bean, sideloaded applications will be scanned for malware.
KitGuru says: We have no doubt other platforms would be at risk just as much as Android if they were more open.