After we have seen what happened to Parava,it is good to know how to avoid bad domain name registrars.
Parava alleged to have kept renewal fees instead of paying them to VeriSign,so it didin't take long for people to notice that their domains had different expiration dates than they expected.So,be careful that the registry and registrar expiration dates to match.
You should also know that the registrar should be accessible in a public forum.Also,if they never send a representative in person to a domain conference you should start being worried.
Of course there are many other signs but these ones are the most important.So be careful and choose the right domain name registrar.