In Outlook...
In Gmail...
View messages and their replies by default as individual entries in your Inbox
Group messages and their replies by default in conversation threads so you see multiple related messages in one view
Spell check automatically while composing
Check spelling after composing
Attach and forward multiple messages
Forward all or select messages in a conversation thread
Delete messages, typically to save space
Archive messages to declutter your inbox
Sort messages by sender, date, or size
Find messages by sender, date, topic, and more using Gmail
Organize messages in folders
Tag messages with labels
Assign color categories to messages
Color-code your labels
Flag important messages
Star or add markers to important messages
Manage incoming email with rules
Manage incoming email with filters
Flag messages for follow-up
Add messages to your tasks list or a Follow Up label
Get desktop mail notifications via Desktop Alerts
Enable desktop notifications in Chrome
Share a mailbox
Delegate your mailbox to individuals or use Google Groups to share more broadly