If your going all the way adept-> paladin -> crusader I think that is stronger than adept -> celestial -> stargazer.
You still have 2 learning bonuses for celestial magic (not 3 like stargazer) but you have WAY more armor weapons plus crushing blow. Stargazer also has some useless things like 10 ranks in scout!?
If your building a different tier 3 class and need pally or celestial to go along (you do realize you get 5 classes total, right?)...Then it depends what your plan is. Are you going to be a celestial caster with fighting (3rd tier fighter class), then take celestial as you should have enough armor weapons learning bonuses anyway and might want some magic. But if your going 3rd tier mage class then you can use arcane magic instead and just need a little celestial. Then take Paladin. Does that make sense? I might be wrong but my theory is to take something magic and something armor/weapons.
If I play again I want to play a samurai/crusader for wicked bleeding 2 weapon skills and a whole lotta weapons/armor
claudius