I've submitted apps to both stores many times.

I hesitate to use the word "rigorous," but Apple's process is certainly more involved, though I'd say it's also bureaucratic and even arbitrary. Their primary concern is clearly maintaining their tight control over their users' phones, which is an extremely lucrative monopoly. The play process, by comparison, is definitely lighter, though I don't know if I'd be comfortable saying it's less well vetted.

Philosophically, relying on either of the duopolies to screen the software we use for safety is ultimately a bad system, especially since they are creating this problem. Until very recently, the internet existed on websites. They are pushing us to use mobile apps because it is more lucrative for them. Apple takes something like a 20% cut of every single transaction that happens on any iPhone app. They don't even allow non-apple-webkit browsers on iOS, meaning that the iphone's chrome, firefox, etc. are actually different than Android's. They do this specifically to hamstring mobile browser development.

They've managed to align the incentives here by offering tech companies more advertising revenue through the mobile platform. Basically, if you make a mobile app, Apple takes a huge cut each time your users pay you, but companies also get to spy on you more, meaning more lucrative advertising.