Since you said it would be automated, a security issue would be how you plan on storing the password. I would hope you planned on putting it into a encrypted file. Depending on your company's policies that may or may not be enough.

Also, IIRC Microsoft Exchange server is particular about the package sizes and you may have to work with your IT service team to see what is the optimal packet size for the server the way they have it set.

Lastly, you say you are going to download attachments. Is your script set to always download all attachments or to just download those it has not already downloaded? If each time it runs, it re-downloads all the attachments, your program can quickly become hog on the server and the network depending on how often you plan on running it.