I'd recommend the FTB Launcher, which is somewhat easier to use, is much more up-to-date, and actually got permission from all the mod developers. http://feed-the-beast.com/
Currently running a Tekkit server, but I'm watching FTB. I'm waiting for them to add Redpowder/Thaumcraft first. Shame the worlds aren't compatible.
Once redpower is compatible with 1.4.5, they are adding it.