This is a great effort, when you are talking about response time, it is ping response. Also, it would be a ping response on their primary site (which will usually give you 100% uptime). But, it depends on the response time of the shared Hosting server, where the websites are actually hosted - and what is the page load time. For instance, BlueHost on their primary website has 100% uptime and with a great response time. As soon as you get onto one of their servers, I have seen website page load time shoots up to over 30s.
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.