I like to check my flight itenary on checkmytrip.com. The main reason is that while airline's webpages and check-in systems often don't provide some information out-of-the-box (for instance the aircraft type), checkmytrip seems to have the information ready all the time. (Yes, you can request the airline to tell you what type of aircraft will be used, but usually by a phone call or so, which is not convenient).
However, quite often it happens that the page simply doesn't load. Is the webpage overloaded? Is there any alternative that would provide the same information?