I'm sorry to sound rude, but yet another crappy survey from MS prompting for the answers you *think* you should get.
I don't use the search. No opportunity to explain why. The reason is that the built-in search is crap, so I use LookOut.
No exploration of filtering/filing and how you use those features. I filter a bit, but not as much as I could, because I'm finding the use of folders increasingly constrictive. It's easier to leave most of my emails in a swodge and search them with LookOut than to file them. If Outlook allowed message tagging (and the ability to apply multiple tags to messages) and then the ability to file messages by tag, I'd be very happy. Like Gmail (oops, I mentioned the devil).
Finally, "conversation view". I don't use it. Why don't I use it? Because I think it's crap. Why do I think it's crap? Because it breaks all the other conventions of threading that most other mail clients use. Yes, we all know that MS likes to do things in their own *unique* fashion, but willfully flouting conventions for no apparent functionality gain is ridiculous. I have to admit that MS mail clients' way of breaking normal message threading has been one of my pet peeves for years. Not everyone in the world is an Outlook user, and I don't see why Outlook won't "play nice" with the conventions. Here's hoping some of the recent bleating about "interoperability" from some of the powers that be starts to filter down.
As a final point, I think if whoever designed these surveys gave a bit more room for comments, they might actually get some constructive suggestions out of it.