Well, even if it's not 'an exact science or formula' that you apply it sure as hell works a treat! I was guessing that the strategic use of reverb and chorus FX would help it all blend together but I'm sure that's only when the slicing is done with the precision and care that you invest in it.
I also use Loop Cloud, oddly enough after you signposted me to it in another thread, but I mainly use it to process and pitch change loops etc as a stand alone application rather than using it in its VST version. I'll usually get the loop processed to my liking and then transfer it into the DAW as a WAV, before starting to slice and rearrange as necessary there. However, after reading your comments it does seem to make more sense to actually use this facility in Loop Cloud itelf.....