Based on their sales report.
Their quarter reports to be exact, GM has been suffering a huge loss on every quarter. Maybe a minor gain here and there but not enough to resurface. With that said, It is not that Toyota is "better", it is the fact that our current giant GM is losing money thus letting the Japanese rivals to catch up quick. On top of that their "junk" status gives them a harder time to borrow money.
A good source with neat tables and cash flow, balance sheets etc.
http://host.businessweek.com/stocks/...OTATION=266152
http://money.cnn.com/2007/03/07/news...rime/index.htm