Sorry - delayed response - Reason is not an arranger program in the least. But it is one of the most intuitive and fun softsynth studio programs on the market. I use it a lot but I'm an old-school synthesist anyway so Reason works and feels just like my recording studio from the 80's with modern devices and conveniences. I think Reason is a terrific value and highly recommend it - if you're curious there's no "reason" not to try the free trial download:
http://www.propellerheads.se/

and don't forget to download this handy generic freeware ASIO driver if you don't already have an ASIO-compatible soundcard:
http://michael.tippach.bei.t-online.de/asio4all/