I also agree that they seem inline rules wise with everything else.
Its basically 2 Ironclad dreadnaughts combined with 2 battlecannons toughness/points wise, and noone complains about ironclads or battlecannons.
These things seem to be built to counter things like wraithknights/riptides(give em the D) and parking lots full of str 7 guns, but strangely enough would have a hell of a time against a handful of marines with a few meltabombs.
I vote yes for the Meta breakers that they look like.
(and these things are a Melta Sternguard's wet dream)