Its a question of flying style, and if you're opponent regenerates shields faster than you do.
If your opponent regenerates faster, then you will want to keep the battle going so they dont have time to regenerate. If you regenerate faster, then its in your interests to move off and regenerate shields, since this will give you an advantage.
Fed ships traditionally have had more labs, and therefore better shield regeneration than equivalent hull classes in other races. Fed ships generally have better shielding as well. When fighting a Fed ship, then, it is in the opponent's interests not to allow the Fed player time to move and repair shields, and kill them quickly. In an even match, the Fed player is utilising their ship's capabilities better by allowing shields to recharge knowing their enemy's shields will still be weaker.
Personally, I would prefer better shield regeneration than a few extra points of armour... over time, the better shield regeneration will outweigh the extra armour, but only if you take advantage of your ship's capabilities.