I think I'm a somewhat casual collector- I take any opportunity I get to root through all the figures when i'm at a store that carries one, and tend to see a few I kind of want but don't buy yet because I don't care quite enough to spend the money on it rather than something else (I still don't have an AT-AT driver...), but then I'll buy the ones that I care about most (Carbonite Han, Boussh Leia, still looking for a Boba Fett, etc.) and there's a few I find out about and outright
need, and search for ravenously (VTSC Han gets this treatment currently for example).
I tend to do almost as much buying of things I missed in stores off the internet though. I'm still catching up on some POTF2 figures, and while there aren't a ton I want, I only own two POTJ figures! From nearly every set of figures there's some I want and don't have yet *coughcoughMaraJadecough*, and I missed many lines altogether such as the VOTC. So much like how I tend to buy video games, I'm a bit behind rather than "up on the latest."
The Saga Collection hasn't changed this position at all really- if anything it's got me more interested than the ROTS line simply because the line covers all six movies, and tends to put 50% of it's focus on main characters that I'm a lot more likely to want to buy (Nemoidian Warriors and yes, even Clones can be super-articulated and wonderful, but I'm less likely to buy them than a cool but less poseable Han Solo- of course, the ideal for me is super-articulation and good sculpt on a charachter I like, such as VTSC Han

)
The line's definately not perfect, but they haven't really lost me with it. I'd love to see more in the way of articulation, higher prices suck, etc, but there have been quite a few figures in the line so far I'd call "good" and the potential is there for them to make a lot more stuff that interests me.