I can't say exactly how you'll feel, but I can't say either the Paradox or Mad Dog gave me that eureka feeling when I first heard them. I think they will grow on you, however. I found it strange going from colored headphones to something much more neutral, and it can take some adjustment time.
I'm not sure what headphones you've listened to, but just understand that many headphones compared to the Paradox or Mad Dog will likely have a more colored sound, higher distortion, and overall slower decay in the sound. I think you will be more satisfied with them if you keep this in mind and don't set up any expectations before listening. :)
I would also highly suggest looking into a better DAC/amp setup...maybe something like the Schiit Magni/Modi combo for $200. That will help you realize the Mad Dog's potential. Other good alternatives include the O2/ODAC, Leckerton UHA-6S Mk.II (can be a bit quiet on well recorded/mastered tracks with low gain and high dynamic range). I know that's probably not what you want to hear, but I'd divert my funds towards gear like that instead of more Fiio stuff. ;)