Vacuum Cleaners Discussions

I'm set on purchasing a Miele canister. Need some insight with real differences between the two lines - S2 and S5. Looking at straight comparison up on web I don't see significant differences in the unit itself. For e.g. http://www.allergybuyersclub.com/vacoverview.html For the most part it looks like main difference is in the bundled attachments, such as, power head, brush. Motor is the same, suction & air-flow supposedly is similar. Does it mean that if you throw higher end power head, floor brush that is bundled with Callisto over to a Delphi then Delphi becomes pretty much similar to Callisto ignoring cosmetics such as ergo handle etc.?