I pretty much agree with the consensus of this thread. From the start of the series, Colin was one of the celebrities that I looked forward to seeing the most. He certainly didn't disappoint. Previously, I was impressed with his technical ability - he simply possesses a natural rhythm, fantastic control over his limbs and an athletic discipline that has translated well to his dance training. Though purists may point out faults, in terms of observing Colin at a technical level, I appreciated his dances. However, I did feel that he and Erin lacked something and that he really needed to immerse himself more in the performance, much like Darren does - whose personality you can see more demonstrably in his dances.
Now, after having seen yesterday's performance, Colin has shifted gears. He must have known that it was the quarter final and that it was time to up his game. And he did. I think Erin did as well because this time she produced routines that I felt were much more memorable. Moreover, as many have commented here, they really connected in the dance. You no longer had two people striving together for for the same goal. That Rumba saw them forge a real partnership, based upon hard work, trust (Erin must trust him a lot for him to touch her so intimately in a dance like the Rumba) and innate ability.
I've made it no secret that I would like a guy to win this year's series of SCD because whoever we would be an inspirational figure for men to take up dance. Darren would arguably be a fantastic ambassador for this role, but considering his superior dance ability, overall consistency, high workrate and kind personality I have to say that Colin currently has my vote.