I have no experience with Siebel, but would like to (or need to) learn about it in detail to program and test Seibel-based applications.

I would like to know, from some more experienced people here, how complex is Siebel when you need to go in detail? How difficult is it in comparison to, let's say, using the eclipse api to program eclipse-based apps? Or something in that range.

This is a very vague question, I know. And probably the only way to really discover how difficult it will be to learn anything is by trying. However, the experience of others may help me better estimate the amount of time and effort that I should (need to) put into it.

Thanks for any input.