Aidy and Cecily are great. Vanessa is very good at what she does and it's not some annoying schtick like Kristin Wiig had. Kate is really good at the W/U and pre-recorded skits, but she usually creeps me out in the live skits. Nasim is always pretty good in her supporting roles and when she does stuff like Huffington and Kim K. She won't ever carry the show, but she's a very solid supporting cast member.
I think Colin is getting better. He'll never be a Seth Myers, but I think he'll compliment Cecily nicely for awhile. I also think Brooks Wheelan has the potential to be good.