I've heard the 704 S2. To my ears, they are a very articulate speaker with a "fast" sound. The only downside is a bit of harshness in its high frequency response.
The Parasound Halo Hint 6 is a nicely warm sounding integrated amplifier that should match up well with the more forward nature of your 704 S2 speakers. It sounded good with Monitor Audio Silver 300s, but was too relaxed and lacking pace with a warmer, softer sounding pair of Paradigm Reference 95F speakers. Your 704 S2 are even a little more forward than my Silver 300 speakers so I imagine the Parasound Halo Hint 6 would also pair well with your speakers.