Laden [sometimes 'loaded'] to the gunwales [pronounced to rhyme with 'funnels']
Stuffed to the gills
They both mean "as full as possible"/"overflowing"/"so full as to be uncomfortable [the second one] or dangerous [the first one]"
The ad is talking about badly written ads (of which, it seems to me, this is one)
ps Finding the meanings of 'gunwales', 'gills' and 'cliches' are left as an exercise for the reader