I remember meeting Andy on a plane to SFO. I've run into him before at Extreme Startups. He was on his way to a board meeting at A16Z, and I was on my way to leave Instagram. They needed an Android lead. After a few meetings, I ultimately decided to pursue my own startup.
I think one of those meetings was with Oleg over the phone. Intelligent guy from what I gathered. I'm sure he'll bounce back, though I'm not sure it's very wise to be so public about this so quickly, when emotions are raw and high.
500px is definitely one of the better known startups here in Toronto. They have a great product, they just need to settle on a product direction and execute. The comments about employee churn aren't surprising to me. And the unfortunate part about startups is that failure is typically the result of internal turmoil, so here's hoping they iron it all out quickly.