fronts the bigger pain in the ass... it holds your engine and entire front suspension/steering together.Which one is the larger question - front or back?
Front isn't very common, the few I remember having that happen were used off road/on dirt roads to clog up the drain holes with mud.
theres a reason i have an I beam across the walls in my garage i just strap the body up and hang itSee I would argue the rear is more work.
Having done both the rear is hard to do to figure where to put jack stands. Getting the bolts off and the way the arms are under tension make it more to man handle.
The rear gets all the road spray on it from the front tires so think the rear can rust out more.