As stated before, the 200MHz SGX543MP4 in PSVita should be in the same ballpark as a 280MHz Cedar (a bit above, maybe), or a ~550MHz RV610 (or Radeon HD3200, as you called it).
Of course, given their nature, these chips will never be directly compared..
The SGX545 in future Atom tablet solutions may eventually be benchmarked against a HD3200 (and probably fail miserably), but it'll depend a lot on driver development for PowerVR solutions for windows, which has been nothing short of awful until recently...
I think the next time we'll see a real competition between PowerVR GPUs and AMD GPUs should be if\when Intel brings Series 6 into future Atoms, in order to compete with AMD's E and C-series APUs.