I'd say no on the reavers, not with all that stuff just hungering for special weapons and such. For smurfs (I haven't lost yet against my space marine player friend yet, who just so happens to play Ultramarines) I would take the following list. Same actually for all of those, can't specialize a whole lot at 600 pts. Though against nids, depending on whether or not he takes a horde or monstrous creatures, you might want to shift points around to give the 10 kabalites a dark lance.
Haemy w/ liquifier - 60
Warriors x 10 w/ blaster and splinter cannon in raider w/ splinter racks, night shields, and flicker fields - 215
Wyches x 9 w/ hydra gauntlets and all equipped with Haywire Grenades in raider w/ night shields and flicker fields - 198
Warriors x5 w/ blaster in venom w/ splinter cannon and nightshields - 125
or shave those upgrades off (NOT THE SPECIAL WEAPONS) and take another 5 Kabalites footslogging it, hugging cover and grabbing objectives.
-Come, join me in my realm of shadows, I have a new game I want to show you.- Archon Hedonus Vex, Kabal of the Red Shadow
1st place: 0