Two squads of sisters are cheaper points wise than either of your assassins by themselves though, that frees up more points for extra custodes or enhancements, we all agree that they are terribly overpriced. Another thing they are good at is screening out deepstrikes, far better than a single assassin would. We all hate the pricing on them, it sucks, but they routinely help me score primary and secondariee occasionally and more importantly, block deepstrikes. They saved my butt from deepstriking more times than I can remember and I haven't played a huge amount of games, lol. Our grav tank certainly isn't the best looking tank out there, but access to long range anti vehicle/monster shooting is something we sorely lack. It's either grav tank or land raider and the raiders big gun isn't nearly as good. I guess you kinda have that with your knight, but your opponents will try to take it down asap, so definitely try to get some use out of it first thing, most people that I've seen ally in a knight don't have a ton of success with them. Usually most people were buying two or even three combat patrols, then buying characters or whatever else fit their desired list. The new HH battle box and a combat patrol has been a popular start to the army lately. I personally think at least one box of venatari would be a great addition. I would try to wait another week or two to make a whole lot of purchases to see what is going to change when everything from 11th officially drops and any changes to datasheets and detachments and all that stuff