yes, no doubt for a corporate environment where office 365 and outlook collaboration is important to exchange online mail service from Microsoft is a good option. but the problem star when people are sending mail large size attachments overall example any correction again the same mail trial gets new file so size of mail is getting increased yes there is option as Office 365 subscription Skydrive comes with 1TB size and we can upload files and just share mail link any changes on SkyDrive file no need to reference again (Cloud service article i already covered the sharing part).
Now as for Office 365 exchange admin we will see how we can decrease default 35MB attachment limit to more relevant example 5MB.
1. Login to office 365 portal as Administrator (https://portal.microsoftonline.com) in lift side select Exchange.
2. In Dashboard Select Recipients.
3. In Mailboxes select 3 dots and click on Default message size limit it will open a new popup box where the default is 35480 KB.
4. Now we can specify mail size limit as per new requirements I change to 5MB out and 6MB in for safer size.
5. Click OK and it’s Done.