To paraphrase, this is the web based email service formerly known as Hotmail and Windows Hotmail. With approximately 360 million subscribers, it is one of the larger email services and is owned by Microsoft. While I was not able to locate the maximum amount of storage using Windows Live Hotmail (Hotmail) they advertise as "ever increasing storage." Last year the liveside.net website showed a maximum storage amount of 500gb which these days might be considered unlimited. You can attach up to 25mg to an email message which is currently the standard for most email providers.
One of the advantages of Hotmail is the ability to change the interface and look of the webmail page very easily. You can set up your reading pane to preview messages before opening it. A lot of people like this ability as you can see the message and delete it without opening it. The preview pane can be on the right side or bottom. Another feature is the "Sweep" function. This can be a great function for cleaning up a cluttered mailbox and is a very useful tool. With this function you can select a message or message group to clean up. You can delete all or move to a folder. There are more options and the choice is yours. Further if doing a sweep by email address, you can easily set up a filter for all future emails from that address.
Like Gmail, you can also view messages by conversation which keeps all messages on the same subject together in an email stream.
There are concerns mainly with the contacts list which is used with many an email message. Using the contact list is not the most user friendly. When importing to Hotmail, I found that I needed to go to each email address and edit the address so it appears like it did prior to importing. You also cannot delete all of your contacts at 1 time. At most, you can delete 25 contacts at a time. While your Gmail contacts cannot be deleted all at once, you can delete up to 100 contacts at a time. I did not find the import feature too friendly when importing your contacts file. I needed to search for the way to do this. Same goes for importing Yahoo contacts. You may be better exporting your Yahoo contacts as a .csv file then importing that file into your Hotmail contacts.
In addition to what has been noted, having a Hotmail account gives you access to other features of Windows Live. It may work for you.