I had my own site when I started. I came over to Tapastic because they had built in features I wanted to incorporate into my site. My own site is still up. I frame in the Tapastic pages so that no matter where a reader comes from they are hitting the Tapastic pages. It helps me because it gives me the comments, subscribes, likes, and access to the larger Tapastic user base, which I would not have if I wasn't hosted on Tapastic. Meanwhile, I can build other features and such around Tapastic, like my Wiki and my gallery, which Tapastic doesn't have.
Note to Tapastic - New feature request, add a Wiki and Gallery section for each webcomic so creators can turn them on and build them out if they want to.
I've looked at some of the other hosting sites, DrunkDuck and SmackJeeves, and they have been Byzantine and difficult to manage. Tapastic is a much better platform, at least for me. I do like some of the aggregators, TopWebComic, Comic-Rocket, Comic Belfrey - who list, but don't host comics. They link back to your home site (Tapastic for instance).