Anyone who has teenage daughters has to deal with GHDs (at least till straightened hair goes out of fashion).
Speaking from experience (well my kids' experiences, and those of their friends), don't bother with a cheaper brand, GHD are definitely the best.
If the GHD does go belly up, there's a guy in the UK on ebay who repairs them at a very reasonable price - just do an ebay seach for GHD repair.
And train the little darlings not to leave them plugged in, because this tends to happen a lot, they get very hot and it's not pleasant to step (or worse, sit) on a fully heated GHD!
We got ours from Peter Marks, I believe.