I think Tiger's right -- Flux seems to be all about the arps and pulses.
If you're just looking for mallets, I have Vir2 and like it a lot. It's probably my first go-to for mallets -- very convenient, because all the instruments are in one interface, so you can quickly try out, say, the glock versus the song bells and see what's working for you. There are more beautifully recorded mallet samples out there (Soniccouture, e.g.), and there are also cheaper ones (Sonokinetic has a nice little library of different mallet types for about 50 euros, and Waverunner just dropped a Vibraphone), but Vir2 is a great, easy-to-use tool that I keep going back to.
EDIT: Also, Vir2 is sold through Big Fish, which has lots of sales. So you can probably nab it for a little cheaper than retail. But NI has a lot of sales, too, so....