What is wrong with CHI straigteners:/which one do you have?

ok so i bougt a CHI straightener for $150 i hardly used it prior to i wouldnt do my hair that much it only lasted less than 5mnth no lie it looked like brand new it would turn on but not heat it really pissed me so i called and get it trade and i paid $25 for a replacement i got in return a CHI nano i was mad it wasent worth it anyways i was gonna callback to get my old one back i felt like i got ripped off but i change my mind because it it heated more than the other one even tough it was cheaper well how about it only lasted a couple of monhts as well today it didnt even turn on :/ does anybody know a good straightner to buy i do have thick hair the hotter the better. from experience what brand have you bought and how long have they lasted? thanks...mines dnt seem to last longer than half a year. so if you have chi what type is it and how long did you have it for?