I'm using the 9th edition of Thomas for a distance learning course. It's a good, sturdy presentation. I'm reading Richard Courant's Calculus and Analysis Vol.I concurrently because I plan on studying higher math down the road and I want to get my feet wet with some more rigor.
That's not to say that Thomas' book is dumbed down. It takes thought and effort. But it's so straightforward that sometimes I feel like it doesn't challenge me to develop the concepts on my own. Anyway, I like using the two books together. In that way I can choose the appropriate level of difficulty depending on how readily my brain is absorbing a given topic.