I actually really like the 128rc. It's super cheap (~$80) and lightweight, but very smooth in general, and with a camera as light as a DSLR I find it much easier to get truly fluid moves with it than with a larger head like the 501. It has no counterbalancer or anything, so it's not great for things like event shooting with a long zoom lens, but in general that's not the type of thing I'd use a DSLR for in most cases.
I have it paired with a set of manfrotto 535 carbon fiber legs and a 75mm ball head kit for a package that travels really well but still gives a solid base and very fluid moves. That puts everything at about $700, but if you go with aluminum legs instead the whole package would cost less than $300.