Comparing tclean to clean with the following parameters:
clean(vis=vis0, imagename=myimagebase, field="", spw='', mode='mfs', outframe='LSRK', interpolation='linear', imagermode='mosaic', multiscale=multiscale, interactive=False, niter=1000, threshold='100mJy', imsize=imsize, minpb=0.5, cell=cell, phasecenter=phasecenter, weighting='briggs', usescratch=True, pbcor=True, robust=-2.0) tclean(vis=vis0, imagename=myimagebase, field="", spw='', outframe='LSRK', interpolation='linear', gridder='mosaic', scales=multiscale, interactive=False, niter=1000, threshold='100mJy', imsize=imsize, mask='auto-pb', specmode='mfs', cell=cell, phasecenter=phasecenter, weighting='briggs', robust=-2.0)
Note the very bad cleaning instability creeping in in the clean image: