Hi,
I got the woofers, but unfortunately it will be very hard for me to do a good comparison. The reason is that I built new speakers which are 6 cm wider (50 cm total) and have 7.5 cm wings on the back for support. The OB-A15Neo's goes a little deeper, with a few extra db (2-3) down to about 40 Hz. This may be just because of the extra width and wings. Other than that their frequency response look very similar.
I used the Beta 15A's in a 3-way up to 150 Hz. Now I have tried the OB-A15Neo's in a 2-way with a 3.3" full range driver crossed at 400 Hz, and a 2-way with a 1" compression driver (CD) and horn crossed at 950 Hz. There are very different configurations, which also makes it hard to do a comparison. But I can say that the Beta 15A's seemed to run out of xmax sometimes, while the OB-A15Neo's never seems to move more than 1-2 mm on same listening levels and music.
The OB-A15Neo's sounds really good crossed as high as 950 Hz, with a CD horn matching it's directivity at the crossover point. I dont't think the Beta 15A's would sound as good in this configuration. I think both are great woofers, but the OB-A15's are better. But if crossing over low (about 150 Hz) it might not be worth the extra cost.