0.20g BBs are generally only good for close range indoor games. Outdoors they are very poor performers regardless of the fps they are shot at, due to their instability even in light breezes (meaning they will go where they want to after 80ft or so), and the inability to do well penetrating dead grass or leaves (they bounce right off, causing you to either change your position and/or expend more ammo to get them through to your target).
To partially answer your question, going by the brands you listed, Airsoft Elite and BB Bastard's new batch are very good (I only use the 0.25g), haven't heard a lot of bad stuff about the KSC brand, TM is pretty good, bio............. meh, there are many people that avoid bio BBs because they don't want to deal with replacing AEG parts due to crappy bio ammo.
This is the best place for you to get pretty much any info on airsoft. Includes two BB brand reviews/comparisons.
http://www.airsoftmechanics.com/