Should I update from the LR3 to the 4 or 5?

Basically what the title says, I currently have the LR3 and am looking to upgrade but I'm torn between the LR4 and LR5. For anyone who has upgraded from the 3, did you notice a big difference with the 4 or 5? I’ve seen a lot of mixed opinions about the 5, so I’m wondering if it’s actually worth the extra cost or if the 4 is the better or more reliable choice.