Which is the better, the Event or ProAc crossover? I don't know. I'll give you some thoughts, for what they are worth.
I am not that much of a crossover expert. I have heard of the ProAcs, not of the Events. That possibly might mean a better sound for the ProAcs but that is sketchy speculation at best.
The ProAcs are 8 element crossovers, the Events 6 element. The ProAc design seems slightly more sophisticated because on both the high pass and low pass sections, the series component is broken up into 2 parts with a parallel element between them. In the crossover world, however, where simpler frequently equals better, I can't say that's necessarily an advantage.
I have not had experience with either of the Scanspeak tweeters. The event's cost $76 at Madisound, the ProAc's cost $56. Each.
If you take a look at the dispersion charts, you see that the 3/4" ProAc tweeter has better dispersion than the 1" Event tweeter. If you take a look at the bottom line-60 degrees off axis-the difference becomes fairly large. That would tend to indicate that the highs on a ProAc might have a special "sheen".
However, I have not gotten around to using 3/4" tweeters so I cannot say. And highly priced, highly rated systems use 1" tweeters.
If anyone has had experience on 3/4" tweeters versus 1" tweeters, please jump in here.
Of course, there is some difference in cost. Two ProAc tweeters are over $100 right there, than add the crossover cost. You already have the Event tweeter and crossover.
If you want to spend between $150 and $200 to find out if the ProAc has a nicer high end, that's up to you. You already have a higher priced tweeter and crossover in your possession.