Centurion is good if I get one early enough (I guess, Hammerhead start). Problem is that basic fighting frigates (Lasher, Centurion, Wolf, and the like) are obsolete past the first two systems (Galatia and Corvus) due to low PPT, and the smallest ship I use from that point on are destroyers, once I get enough Enforcers, Mules, and Shrikes from pirates. Warfarer is sad, always the first to die in Apogee starts, and useless at fighting from the very start. Wayfarer was decent during 0.7.2, but now it does not have what it takes to fight in modern releases.
Hammerhead is good, but becomes obsolete eventually. The only loadout that is overpowered is the Safety Override one, and that has low PPT. The non-SO loadouts are nothing remarkable and are not strong enough to cut it late in the game.
I like Conquest, but it is not something I get early. The earliest I get it is looting one from an expedition fleet and/or named bounty during the midgame. Later, I eventually build a pristine one. Conquest blueprint is the easiest capital blueprint to steal (thanks New Maxios), but it may be a while before I get a forge and Heavy Industry. Conquest is part of my endgame fleet. It is handy for times when 60 DP (Paragon) costs too much but Conquest can get the job done.