I'll try to speak for Austrians haha, feel free to correct me
3. Slovenia - their success seems like it will prove unsustainable, but there were a lot of intense games, and the h2h was pretty back and forth, perhaps even with a slight advantage to them. In addition, familiarity is bred by the fact that Austrian juniors play Slovenian juniors from youth hockey up.
2. Hungary - Austria hasn't really lost this one so long as I can remember. But it's another rivalry that is built up from the junior levels, where Austria tends to lose at the U14, and U16 levels, U18 is a toss up, Austria is clearly superior at the U20 and Senior levels. For a while it seemed like it might become more competitive, but that seems to be fading away.
1. Germany - I mean...it's Austria-Germany, who could not love it? We were closer in years past...Germany seems to have taken the bullet train up to the next level, which, good for them. I wouldn't say it was particularly competitive before either, we won once on the U20 stage I think, maybe twice, we also forced OT in the 2014 Olympic Qualification, which secured our ticket to the 2014 Olympics at their expense. Generally, I think we have some work to do to keep it competitive. But it's the derby, gotta love it.