If you are on a budget get the Vifas from madisound. I got rid of a set of my Quarts because I thought the Vifas sounded better.
There are two main advantages in seperates. The most important is the flexibility in the installation that the seperate tweeters give you. The second advantage, as you said, is most definitely in the crossover. The crossover is where the money lies. If you can build you own, you could blow away anything on the market for quite a bit less money, but most people can't without expensive test equipment.
A couple of years ago, upgrading the crossover (to a musicomp) in a pair of Quarts boosted the price by 200.00. The difference was they used higher quality caps and inductors and used a higher order crossover (i think it was a third order as opposed to a second order) This boosted the power handling on the same speakers to double their normal quoted power handling....
anyway, i guess i'm just rambling now...
Dave
