scook
Pentagon is an interesting synth that can also be used as a vocoder. It is old, 32bit only and has a serious bug that can be avoided by altering the factory presets http://forum.cakewalk.com/fb.ashx?m=2708401 It also requires that you run your DAW as administrator. If I had a choice between some VA patches for Rapture or DimPro and Pentagon, I would get the VA patches.
I am not sure about the version you purcahse as a stand alone but the version bundled with Sonar X2 comes with a 64 bit DXi option.
Its more of a traditional synth than Rapture or Z3ta+2. I like it. It does not have bells and whistles like arpeggiators etc. which I never use, just good old subtractive analog emulation.