I think there are 2 opposing parties when it comes to the stereotypical "M-dot" tattoo. Either 1) you love them, have one already, or you only aspire to do an Ironman so that you can brand yourself, or 2) you can't believe that someone would tattoo a corporate trademarked label on their body.
Now I love tattoos. I have 3. I would have more if they didn't cost so much money or keep you out of the pool for 2 weeks while healing. My tattoos aren't anything artistic or meaningful. I have 2 horse tattoos (one is a MY LITTLE PONY!) and a Harry Potter one. I know. Nerd alert. Whatever - I don't care. Most of the time people don't even notice my tattoos for months.
I am probably the first person you would expect to go out and get an M-dot tattoo the day after my first Ironman. And I'm not going to deny that I have the urge. But I just do not want that stupid M-dot. Everyone has it, some of them are crappy, and I don't want to be that girl with the M-dot tattoo on my calf because I have to brag about my Ironman (that's what Ironman-relate facebook status updates are for). It's not even cool looking. I don't judge people with M-dot tattoos, unless it looks like you scratched it on with your fingernail. I considered one for a while but I personally like my tattoos to be more original (hello, My Little Pony anyone?).
I thought for a while about getting an actual Ironman tattoo (you know, the comic book character played by the ever-so-dreamy Robert Downey Jr.). Which would be badass but I just don't have the balls to do that.
I think I have actually come up with my real Ironman tattoo idea which I am keeping a secret until I do it. First I have to finish the stupid race!