I hear they're nice tyres, but they'll drop your BB quite a lot. (you'll be an inch closer to the ground)
There's a constant what-tyres debate going on in bike-polo circles in brief the consensus seems to be that the best for feel and stickiness are gatorskins but are only available in tiny sizes so not suitable for all bikes.
Next favourite are schwalbe Kojak's. The Kojak's being available in the larger 2" sizes (preserves the handling of your bike if you use a similar size tyre to the knobbly taken off)
From my own experience:
Conti Sport Contact are beautifully puncture proof and provide a lot of grip.
Schwalbe city Jet's are very puncture proof slightly less grip than the conti's but wear better.
Specialized nimbus tyres are dry tyres only, wear well and very puncture-proof but lose all grip in the wet.
Halo twin-rail are dangerous in all conditions and should be avoided at all costs. I've never experienced a tyre with less grip in my life.