Yahoo Mail versus Gmail: feature comparison

I've been a long-standing user of Yahoo Mail.  Gmail was a different way of thinking so I was hesitant to use Gmail.  Now that I'm using both their web clients and also accessing the accounts in Zimbra, I'm starting to see each of their advantages and disadvantages more clearly.

	Yahoo Mail	Gmail
Conversations	Not available with the web client although Zimbra does try to collect email into conversations, but sometimes does not associate the correct emails together	Yes, available.  With more use, I've grown more accustomed to it.  Will continue to evaluate.
Search	Yahoo's search is no slouch.  Searches attachments and allows you to further filter by folder	Haven't used enough to judge but I remember when my wife searched her Gmail (in 2009?), PDF attachments weren't peeked into; could be fixed by now
Contacts	Recently (as recently as early 2010), access to Contacts seems to be unstable such that addresses that are in my Contact are deemed to be missing and direct access to the Contacts list is occasionally not available	So far, seems stable
Folders versus Labels/Tags	Folders; simple to understand and use but can have limits since a piece of mail can only exist in one folder at a time	Now that I am using Delicious social bookmarking, starting to understand the power of tags as a piece of mail can now have multiple tags.  More flexible but can be more "work" to organize
Synchronization with phone	Not available with my Windows Mobile phone as far as I know	Yes, via ActiveSync for Windows Mobile so able to sync mail, contacts and default calendar.  For other devices
Open to other email clients	Other than Zimbra, don't know of any other clients	Openly uses standards such as IMAP and SMTP so any email client that understands these protocols can access Gmail
Security	Only on login	By default, uses a SSL connection (i.e. https) through-out.  Although that doesn't mean you can send/receive confidential information as others might be using less secure email clients
Archiving	Equivalent to moving to a folder (can be viewed as both tagging and archiving)	Explicitly available