You usually have to give away personal details when registering. The service is free, so perhaps you can't expect as good a service as if you were paying for it, and if things go wrong you have little legal redress from the supplier. Having said that, there is enough competition to ensure that standards remain relatively high. Make sure you are paying local not national rates. If the plug is pulled on your account, you will not be able to update your site.
Technical support can be expensive.
You'll end up using the web much more, so your telephone bill will go up. All rights reserved.