It's probably a good alternative to tk. I remember reading on their forum a very long thread, a user not really impressed by the service provided. Can't remember exactly what happened to him, but you would better take a look at that or other threads first. Always read the small print.
hmmm. Lets not forget what happened to .co.cc With .co.cc, it was a top service for years, then one day the service was simply switched off. All sites, but also all email accounts were just suddenly dead. All work in terms of traffic and SEO, wasted. Probly nothing wrong with it, but if you plan to keep the site long term, I think it is better to use something else.
I would never use anything besides .com or .net anything else is going to be hard to do SEO and like matt said it could all just get removed one day
Never plan a long term relationship with these programs. Your hard-earned work and time invested would be wasted. *If you would like to learn it through the hard way, take some risk.