Right now I'm running the McDSP Project Studio Bundle on my system at home, but have used these plug-ins on other systems as well. My home studio consists of Pro Tools 9 and a Mac Book Pro laptop that has a 2.2 Ghz Intel Core 2 Duo processor and 4 GB of RAM. I've yet to experience any issues when it comes to performance with these plug-ins, as I have a pretty stable system. Even so, they don't seem to be taking up too much processing power.
I got the McDSP Project Studio Bundle LE a few years back when I took advantage of a student deal that they were having. I got the whole bundle for only $100 US dollars, which is about a third of what it actually costs. This bundle is now known as a Native bundle and not LE, although I haven't had the chance to compare them. Even if you don't get a student discount, these are some awesome plug-ins and considering what you get the bundle really doesn't cost you too much. I don't find that any of these are in the circle of my go to plug-ins, but they are a great 2nd choice when I'm looking for something different to try. The McDSP Project Studio Bundle is a great way to build up your plug-in collection without spending too much money...