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: