ive used seal-tite, tex-tite, brownell's and cir-cut's graphite-silicone waxes.
the consistancy of the bohning 'tites and the brownell wax are about the same. soft and very tacky. goes on kinda clumpy, but easily melted into the strands with the fingers.
the cir-cut wax has a blue color to it and is harder, like a candle i would say. goes on smooth and works in ok. i use this type when i'm making strings and after the strings are done and on the bow for a while, i'll use the softer waxes.
the brownell wax is nice because it has a twist-up tube, like a chapstik tube on steroids. makes it really nice to get the wax out of the tube.
overall, any of these 4 waxes will work fine for synthetic strings. not much color bleeding between the black and grey that i use.