The actual Ha signal itself is very very narrow. You don't need a wide filter to catch all of the signal.
However, as Mark just said, transmission values of filters do vary. That is part of what you are paying for with the very expensive filters.
If you believe the Astronomik website, their filter has transmission values of up to 99%. Assuming that peak is actually exactly at the Ha line, that is very good.
Looking at the graph on the Baader website, they run about 89% transmission.
However, transmission is only part of the story. The wider bandpass of the Astronomik is letting in non-signal. And that reduces your signal to noise ratio. In my opinion, unless you have very dark skies, the Baader is likely to produce an image with better signal to noise.
There are other factors as well. It is not unusual to get some haloing around the stars with these filters. I don't know which is better in that regards.
Edited by Madratter, 24 March 2018 - 08:27 AM.