I hunt 75% of the time from a climber and love it...
MOBILE, baby, Mobile!
It took me better part of a season to get above 14-15' and now I regularly try to get in the 20' range.
I too suffer from the shakey knees at heights, but for some reason this never bothers me...
Wait until your in a tree and 30-40MPH gusts whip you around like a rodeo clown - big fun

Good luck!