I'm not convinced Farmar is able to contibute immediately and probably won't come out without a lottery promise.
At this point I'm more inclined to wait and possibly take Dee Brown.
nbadraft.net
NBA Comparison: Erick Barkley
Strengths: The one-man-fastbreak is a blur on the hardwood and if you aren't quick enough, don't expect Mr. Brown to wait for you. While firing bullet-passes, his dribbling and distribution skills are as good as anyone's. A capable scorer, when he decides to show it, he can set the nets ablaze in the blink of an eye. Also a true leader with his constantly moving motor-mouth, expect him to make the All-Quote First Team.
Weaknesses: You first have to look at his size, barely tipping the 6-foot mark. His ability to guard against the bigger guards is still up in the air, but don't think he will fail for lack of effort. Also can get into pass/shoot modes; He looks to involve his teammates immensely and will pass up his own shots for the sake of others, or, where he attempts to tire out the scoreboard operator single-handedly.
Brown is not getting much love on the mock boards and appears to be on the bubble.
BTW, I can't see Armstrong falling to 21. He's got lottery talent and will need a promise in order to come out. Boone is a different story, but I'm not excited about his game and doubt he would be much help.