I actually don't mind canons, so long as the whole thing is tasteful and it doesn't like horrid.
A nice HKS system on an EVO with a canon looks neat, and sounds good.
A 5" turbo canon on a Charaded Daihatsu is fkn horrid and I hope the people inside die from asphyxiation.
Having said that, I typically wish them no harm.
(much)
If you spend the dollars on a good quality canon, and a good quality sub muffler to keep the tone low, then the canon can be 'ok' on an FTO (In my opinion).
Meanwhile, if you have stock alloys, do not get a canon, you need a decent set of rims to back the canon up.