KSS (~$150) - if you like it and you feel that you're playing well with it, buy a reel of it. It really is as simple as that. There's not much point buying something else unless you start hankering for something else or feel that you're after different characteristics.
BHBR (~$80) - great string, doesn't offer ultimate precision in terms of outright directional accuracy compared to the best polys out there, but lovely feel, and a nice liveliness to it. Generates unpredictable action/movement/spin on the ball which can be disruptive for opponents. Big difference between the 16 and 17 gauges. Go for the 16 unless you have a very underpowered racquet as the gauge runs thing. 16 is also more consistent and more control orientated. I find 17 way too lively.
BHB7 (~$90) - great baseliners string, very elastic and springy. Ton of spin and grab on the ball. Playability lasts a long time, easily 8-10 hours, possibly more. Didn't like it on volleys or touch shots as I thought it was too springy which ultimately ruled it out for me.
Volkl Cyclone (~120) - have only tried the 18g. Kept on breaking too easily which ruled it out for me. Didn't like the tinniness, plasticky feel, or the unpredictable power. I suspect the thicker gauges will be better and more consistent.
Gosen Sidewinder (77.50 TW sale) - no experience of this.