It would be wise to consider movement rates of the big caps ships before purchasing one. If you can't get to any given conflict before it is over, owning a Jav could mean it's only useful as an aggressor, and that is severely limiting in your play. Also, it will probably require a lot of money in NPCs to keep a Jav in service. It's of no use without gunners and it is a huge project to organize so many players. You can't just expect dozens of folks will always be ready to hop aboard and then wait two days for a cap ship to enter a theater of conflict.
Long story short is cap ships will be a real trial to use in game. The slower they are, the harder they'll be to use, but this is exactly why they will be the deciding factor when they actually show up for a conflict.