Heard these two headphones and their youngest on-ear cousin yesterday on HiFi Ljubljana audio show and also spoke to their maker Blaž Erzetič.
I will try to describe how they sound but take this with a grain of salt as I am no reviewer nor a headphone expert. Now buckle up and get ready for a minute of my confused mindflow 
About Mania headphones: They are not as dark as in the sound demo but they are on the darker side. Bass is sufficient and very natural, mid-range pleasant but a bit shallow on times (especially female vocals) and the treble is where it should be. I cannot comment sound stage and imaging as I did not listen to my test tracks. I tested them with unknown music streamed from a high quality dac through all four Erzetich amplifiers. They by all means sound amazing but their bigger brother Phobos sounds better in my opinion. Their maker said, his focus was to create audiophile grade headphones that can handle heavy metal. I forgot to ask him why a titanium coated driver but I assume it is to customize frequency response.
Phobos is a very similar headphone to Mania and yet so different. Both are very comfortable but Phobos has the edge over Mania in some way but I am not sure what it is as I only had about 30 minutes for listening. Compared to Mania it has a bit more pronounced but more delicate treble and just a touch warmer mid range. It is overall a better headphone in my opinion than mania but I have to repeat that this conclusion is based on unknown to-me music.
I also compared these two headphones to my Tin T2 with silicone tips. Female vocals are more “meaty” on T2s but the other two provide more details overall. If you are treble sensitive, then Phobos might be a bit too much for you but I had no problems as the treble is managed very tastefully.
Mania, Phobos and T2 comparison:
I sat down on a chair and occupied the 3 expensive amplifiers (they are a bit different sounding by themselves but I determined this difference is minimal compared to headphone signatures. I also mixed combinations in between the test). Mania is the darkest from these three. It sounds like you were listening to music in a hall when you compare it to the other two. Phobos and Tin T2 are similar in brightness but have much different profile. Phobos has more relaxed mid range, clearer highs and more instantaneous bass. Tin T2 is more mid range focused compared to the other two.
In the end I have to emphasize that company founder and one-man band Blaž Erzetič (Blaz Erzetich) is a friendly person and a very good engineer. In his youth (he ain’t old) he made his own audio equipment and then evolved his hobby in a company that we know now.
If you need or want to know anything else, just ask me.