^The Romulan fleet was supposedly in shambles following the Dominion War, so I'd have to give the advantage to the Federation. The advantage only increases once you factor in the events of Nemesis
, as the assassination of the Senate and the division of the Empire into separate factions (with one side being pro-Federation).
The Romulans were the only AQ species having technology that approached anything used by Starfleet. Their vessels were extremely powerful and highly maneuverable. That they had a cloaking device made them even more formidable. But their ships seemed to lack the versatility of the Federation's vessels, as we see only Warbird-
-class ships used. It's possible the Romulans had additional classes of ships that were intended for exploratory missions or science expeditions, but they're never shown on screen.
I don't know what to make of the Romulans' economy. Their people don't seem to be starving as is seen on Cardassia just before and during the Dominion War. But their police state suggests persistent social unrest, turmoil that would only have increased with the growing strength of Spock's underground movement and the seeming dissolution of the Tal Shiar. Recall that Koval was a double-agent secretly working for the Federation in spite of his being the organization's chairman and a member of the Continuing Committee.
As an aside, I don't buy the Titan
novel claims that Koval was assassinated. I think he faked his death and defected to the Federation. Whether a treatment for Tuvan Syndrome was ultimately devised is something I don't know, but I find it hard to believe he'd have allowed himself to be killed by a political rival.