Windows Phone 7's integration with Exchange is exceptional, I've found it really nice for work.
Overall, the entire WP7 package is well done and simple. Now only if they marketed it as much as they marketed Windows 7...
The only complaint i have is with outlook.. But this happens on ios also, and i believe android. If you have multiple folders inside your inbox, you will not get notified if a email is received in one of the folders you created. It wont even make a sound, you have to show all folders in order to see if you have mail in said folders.
Also, I would like to have better options regarding alert tones for texts/mail/calender/etc.. They sound quite similar.
Other than that, i like using it better than my iPhone.
OCD is thinking you have to twist every knob on the stove eight times because you cracked your knuckles out of order, otherwise your heart will explode.
Honestly WP7/WP8 are nothing special.. Once I was excited when i get WP7 phone.. I felt quickly bored and non-inspired with OS WP7 for a month , not hardware phone..I ditched WP7 then went back android phone and happy again...