I personally don't have any but I find them really cool and a great way for someone to express their personality on their skin. However due to there everlasting effect and that I'd probably regret almost anything I chose in a couple years, I wouldn't get one
Not really a big of a deal if you want to do it but the reason is that you must know what they mean to you and why did you do it. I will tattoo my right arm completely, maybe i'll even tattoo my back.