I have use both HR and smartbot in arena. and HR's arena bot is better then smartbot.
run 10 times with smartbot and got 1time 3-3, 9 times 1-3. (I report the suck result to admins and they just block me out with saying nothing)
run 7 times with HR, 2 times 4-3, 5 times more then 5-3. I think it will be better if improve the card pick logic.