My Iphone 4 was Jailbroken and I started having some major issues with it because I cut down the OS to the bare minimum that I could to conserve battery on it. I just found the whole jailbreaking thing to be a messy, and undesirable experience overall. I didn't like how anything looked, felt, or worked. It all just felt majorly silly to me for the 6 months I had it. Most of the time I had to reboot my phone because things would stop working, even in the middle of a call.
I ended up dropping the phone and had to reset it with a black screen to send it back to apple, because Jailbreaking was a warranty breaker at the time. My Iphone 5 (Back when I had it) I had considered jailbreaking but it was just too much of a pain when I just use regular apps anyway. Not worth the trouble. I don't have an Iphone anymore, so it's not really a big deal to me.
I did root my nook tablet with Jellybean a couple years back, and I still have that all working on it, but I don't really use the tablet much anymore since most of the things I read are just on Google Chrome. My HTC One (M8) feels more comfortable in my hands than the tablet does, but I'd like to pick it up and start using it again anyway, feels like a waste if I don't.
Edit: I forgot I did use a phoenix setup for my old PSP 1.0 so I could play some games from overseas I couldn't get here without paying an arm+leg. Bricked my PSP, so I reset it. Still bricked. Ended up turning it on two years later and it had reverted back to the custom firmware and worked again. It was just weird so I reformatted the card and replaced the original battery. The battery life on it was shot, but I just got another PSP and did a case mod on it to make myself happy. Ended up cracking the motherboard on it.
Go me.