by tony » Wed Nov 18, 2009 2:02 pm
It will not slow your website at all. It all depends on how much control you want to give to your client.
If you are going to be sharing your space, then you will be the only managing it as you do not want to give them the Cpanel login.
If you have separate account however, you can give them full control of their site and they can manage their emails, stats, etc. This will also ease the pain of separating the 2 sites at a later time.
Hope this helps,
Tony