As you go up through the "Eras" of the EA fleet, from Early Years, to Third Age, to Crusade, the technology level of the fleet rises (Fluff) and in-game terms, it means that the fleet, generally, gets better fleet choices at higher priority levels.
For example, the best ship the Early Years EA fleet gets is the Orestes Battleship, which, while being a decent contender, is quickly outmoded and outclassed by later ships in the later lists. Currently, I am of the firm opinion that the EY list performs best in 2E, with its lower priority, initiative sink favoring slant.
Third Age is the best of both the EY and Crusade fleet lists, getting some of the precursors to the Crusade lists, such as the Warlock Advanced Destroyer, while maintaining some of the lower priority mainstays, such as the Avenger Carrier, Nova Dreadnought (albeit modified from the superior EY version), and Olympus Corvette, while adding new "iconic" canon ships, such as the venerable Omega Dreadnought. The Third Age list is essentially the "middle ground" of the Crusade and EY lists, and consequently performs pretty well at all priority levels.
Crusade EA is the most 'high tech' of the three EA lists, however, consequently, it suffers, significantly, in lower priority battles. It loses the Raid-level Avenger carrier, depriving it of an effective low priority fleet carrier, its best low priority capital ship is the Hyperion, an aged ship with a short-ranged boresight, and is just decent. The Chronos Attack Frigate is a superlative skirmish ship, however, while its hull 6 and interceptors 2 shield it extremely effectively against normal fire, against beams you'll find it horrendously fragile, and to boot, the ship is relatively underpowered in its Heavy Pulse Cannon. To make up for this, the Crusade EA gets the Apollo and Marathon Cruisers, both extremely effective Battle level choices, and the Delphi advanced scout, a range-less scout with 5+ stealth, making it an effective raid-level scout and a very good alternative to the Explorer scout. Additionally, the Crusade EA list is the only one of the three EA lists with an Armageddon choice, getting the ISA's Victory-class Destroyer, in itself a extremely effective vessel (Though I personally would have preferred the Nemesis, even if it is less effective).