Recently I have been involved in a project concerning the hosting facilities of some of my customers. I was looking at all the options, comparing needs and requests and more.
Several options exist. You can host yourself in different ways and offer that service to your customers.
Pros :

* you are in control of how things are setup, how they work and what you offer exactly
* you can build custommade things for your customers that nobody else has

Cons :

* you have to support it and that could take time (can be nerve-wrecking sometimes)
* your hardware can break, so you need spare hardware and all that

The other option is to go to a hosting company and set everything up with them.
Pros :

* no worries about the provided services
* backups are taken care of
* you have an SLA for the uptime
* offered solutions are maintained by provider

Cons :

* You're not totally in control of what you offer
* it's not your great stuff you built yourself

I don't think I can make a decision liek this for you, but this is something to consider. While it was and possibly still is very popular amongst certain people to be able to claim you run the show, I can always sleep peacefully, knowing that it is cool to host, but a better solution to have your customer's stuff hosted at a specialized company : a hosting provider. The next challenge is to choose the right hosting provider.....