I always aim to jailbreak any iOS device I have (iPhone, iPad, iPod, etc.). Primarily I do this because I believe consumers should have full control of the hardware they own, without having to operate under the constraints of the Apple nanny. Also, jailbreaking is the only way to effectively block distracting advertisements that eat mobile bandwidth. The AdBlock app on Cydia (the “app store” for jailbroken devices) only seems to work on the native browser Safari which I don’t use anyway. A repository once existed at repo.modyouri.com with an app with nice ad-blocking ability, but the modyouri repo has been down for several months.
I was pleased to recently discover the Untrusted Hosts Blocker which works neatly by modifying the /etc/hosts file to block not just connections to ad servers, but also to other servers that might undesirably collect private information. It has been working well for me so far.