Just an FYI, but that was the least useful bit of the Snowden leaks and is more speculation and insinuation than anything. It's literally based on the reading of a PowerPoint slide. AFAIK, there's been no actual evidence of "direct access", whatever that's supposed to mean. An automatic subpoena-serving could easily be written down as " direct access " on a ppt to management.
It's probably a good idea to not store critical data with any third parties, but I'd be far more worried about Google than MS.
Eh, some parts are clearer than others. A ppt that says "direct access" and everyone coming up with their own interpretation of what "direct" means is silly. Especially when high level engineers have directly contradicted those statements.
I trust Google less than MS because MS seems less likely to go use my data or even get their act together. They seem more legally scared and bureaucratic due to their past legal problems. Google seems intent on making us give up privacy (didn't Schmidt say something to that effect)? My interaction with Google services includes them constantly and repeatedly asking me to turn on history or other tracking systems. Even when I constantly decline, they keep returning. Google's main goal is to datamine to sell advertising, so that's sort of fundamentally in conflict with my personal values. Android permissions is another shining example (and now, at version 5, what exactly is the excuse?).
If Bing ever took off and replaced MS's real revenue, then I suppose I might feel the same way about MS. But that whole division, the MSN/Live/Bing/whatever, seems mired with idiotic managers that can't get anything straight (hence them losing to Skype, not turning MSN messenger into a real social network, repeatedly rebranding and offering random services then discontinuing them, etc.). They did have some great engineering though. But even if they were intent on malice, I'm not sure they'd be capable of pulling it off due to the legal/management part getting in the way for good or bad.
Overall, I give MS money, so I'm their customer, for the most part. Not true for Google, at all.
It's probably a good idea to not store critical data with any third parties, but I'd be far more worried about Google than MS.