Jonathan is ditching his iPhone 5s and moving to T-Mobile. He's trying to decide between the HTC One, the Samsung Galaxy S5 and the Google Nexus 5. Leo says that the Nexus 5 is the pure Google experience with no added "skins" or bloatware. This means it will always get updated right when Google releases a new version of Android. Leo likes the HTC One, but it's a bit smaller. Leo isn't a fan of Samsung because they put too much bloatware on their phones. The Galaxy S5 isn't bad, but has a cheap plastic feel to it.
Yes, but you'll have to root the phone first. The XDA-Developers Forum is a great resource for asking questions and learning how to root your phone. Once your phone has been rooted, you can backup your phone using an application called Titanium Backup. It will back up all apps and settings. There's both a free and pro version in the Google Play app store.