Romulans were the original inventors of the cloaking device (at least according to canon at the time), so their version was probably superior.
That's correct, although there's no way to know if they still had that advantage by 2371. Their alliance with the Klingons was formed in large part because the Klingons wanted their cloaking technology, and they wanted the Klingons superior weapons.
By the twenty fourth century, Romulan warbirds were comparable with Federation ships in terms of their weapons, speed, and maneuverability. It's hard to know if the Klingons made similar strides in technology given the economic problems brought on by Praxis' explosion and changes in their military structure to pursue peace with Starfleet. Their ships always seemed to be upgrades of existing technology rather than completely new systems, at least until the Negh'Var class was introduced.