It is pretty focused on multitrack recording, rather than on being a sequencer. So, ITB production is probably better served by other tools (I use Renoise and Fruity Loops, mostly, both of which suck for multitrack recording; lots of folks like Ableton Live). Reaper has a sequencer, but if what you want is to compose ITB or the remix with loops, there are better tools.
But, if you're recording live instruments and mixing and mastering the resulting multitrack recording, Reaper really is among the best in its class, and comparable to tools costing many times more.