In particular, Web Hosting Hub uses BoldGrid as a site builder. BoldGrid is actually an add-on to WordPress, so there's no lock-in. This overcomes the major problem of most site builders: you're locked into that host and that tool, often requiring you to completely rebuild your site if you want to expand. By using a WordPress-based solution, all of the rather considerable power of WordPress is available for future expansion.
Many web hosting services offer so-called unlimited or unmetered service for whatever amount of bandwidth, disk storage and sites you use. It's important to understand that most terms of service actually do limit the definition of "unlimited" to what's considered reasonable use. The bottom line is simple: if you're building a pretty basic website, unlimited means you don't need to worry. But if you're trying to do something excessive (or illegal, immoral or fattening), the fine print in the terms of service will trigger, and you'll either be asked to spend more or go elsewhere.