personally, I find that the Enforcer is quite effective against the other two heavy cruiser types.  esp against the Destra Crusader.  The kodiak just seems... primitive i guess, and the Destra has less hull points

THe enforcer also has an ability that repairs it at 18 hp per sec. its not as good as hoshikoes but it can be annoying to micro the enforcers that are being attacked to repair. it is a good way to survive against a SB for longer.

I think the enforcers are the most independant HC because they can repair themselves and slow other ships down with a teir 7 ability. a fleet of enforcers alone could cream any equal fleet of only other HCs. But that doesnt help much with a balanced fleet, but I still think enforcers are the best.

You don't consider each unit alone, but in the context of the rest of their fleet.  One of the big advantages of the Kodiak is that it shares its damage upgrade with fighters and flak frigates.  On the other hand, the Advent and Vasari heavy cruisers share their damage output only with capital ships (and siege ships, but they don't deal appreciable damage to begin with).  There are no questions that the Vasari have the best special abilities on their heavy cruisers, which leaves them in a good position.  The Kodiak also has a great synergy going with the hoshiko.  The only heavy cruiser that really seems to lag is the destra.  Its special ability is nothing special, and it doesn't fit in well with the mid-range units that form the bulk of a standard "battleball" formation for the Advent.

Nah I love my advent but the destra is a very expensive and difficult ship to bring to a fight.  Typically you won't have researched plasma upgrades at all until after you start pumping out destras, and at the point you can get destras, it is only another temple or two before you can start doing armor increase research.  Do that instead and your illums are nearly as good armor wise as base level destras, plus you already likely have laser research high and that helps both your bombers and your illums.  If money was no factor and you could afford the upgrades, the destra becomes a decent ship..HOWEVER.

As I discovered against a well informed opponent, the destra only has heavy armor and it shoots a composite that "only" does full damage to light frigates.  Cobalts are cheap, costing nearly half the value of the destra each and they can be pumped out very quickly.  A swarm of cobalts with upgraded armor can outlast and kill a much more costly fleet of destras.  The obvious answer is a mixed fleet.. which means you're back to throwing money all over the tech tree again to get everything upgraded.  Illums only with a push for armor upgrades seems to me a better option.  Another thing.. destras have a horrible turning speed.

Ah another point though.. against the marza barrage, destras have a much longer lifespan than illums.  Something to think about.. better to push the damn marza with guardians and use bombers (with laser upgrades) to take out the marzas I suppose.

Personally I dont use destra crusaders much.  There are some rare instances where I might use it, but as I'm learning to use repulsion for the guardian better I find I have less use for Destra crusaders.  I only use Destra crusaders when I find I'm combatting a large amount of heavy cruisers, but again those can be kept at range using repulsion.