For the sake of comparison 1and1 offering unlimited is essentially untrue, their small print is copied below.
General Terms and Conditions of Service
10.4 Packages with unlimited web space are initially configured with 50 GB of available web space. The available web space capacity for unlimited web space will be checked once daily and, in the event the customer’s usage approaches the limits of the available web space, 1&1 will increase the webspace configuration automatically in increments of 20 gigabytes at no further cost to the customer, but no more than once per day.
Acceptable Use Policy from 1and1.co.uk
2.3 In order to maintain the data-transfer volume restrictions, You agree to check all email accounts in regular intervals and download the emails stored therein. You understand that 1&1 may, should the capacity of your email boxes be exceeded at any time, return all subsequently received emails to the senders without notice to You.
2.4 Email accounts that have not been used for a period exceeding two (2) months (i.e., where You have not accessed your account and You have not downloaded emails) are subject to suspension by 1&1. Upon such suspension, 1&1 will send a notification to your primary contact email address, announcing the suspension of the account. Failure to respond to such notice with a request for reinstatement of the account may, at Our sole discretion, lead to the termination of the subject account and the email box may be deleted from Our servers. In such cases, 1&1 takes no responsibility for the loss of any data and/or emails still located in such account and You have no recourse against 1&1 for any damages resulting from the loss of such data.