I have been on MP for almost a year and other than a few hurdles in getting it setup. I opened a a new bank account for security and accounting purposes and had to switch a few things around but it has been working pretty good. Adjusting to the delay in funding availability took some getting used to but flows pretty well.
From a tax perspective the reports available under MP are a lot better for getting ready to file taxes than the reports that I used to pull from PayPal and had to combine with my own spreadsheet information, eBay sales and shipping data and other information. I can pull that from a single eBay report now and add in a few outside elements like Pirate Shipping costs when I use that service.
I diversified quite some time ago across multiple venues not so much because of MP but other issues with eBay. I still list items on eBay but try to only list things that minimize my risk as a seller or that I can afford to take a loss on. No high value items, no electronics, no coins or precious metals, things that are high target items for scammers.
