For me they have actually been fine except the other day when I had some lag and also disconnected once. It seems like it's usually hitting nodes that only some people are passing through.

I remember they said that they can't directly stop the one in the past because it was being affected for political reasons and wasn't related to SE, so in addition to SE contacting the ISP, they have said it helps for a lot of players to bombard them with complaints too. I'm not sure if that's still the case or not. SE does also routinely contact ISPs to help them setup countermeasures or adjust them to match the new attack pattern, since the attackers change pattern sometimes.

The only thing I can think of to solve it at this point is for them to just move the server to a completely different location.