flat bottom blades are better for training because they provide more lift at similar angle of attack and speed compared to symetrical blades. between plastiblades and wood flat bottoms, you trade light weight for durability. the added weight of plastiblades can additionally slow cyclic response. you can also add weights to the flybar shaft if you desire slower cyclic response.

however, by slowing the helis cyclic response to compensate for "dramatic thumbs" will also make the heli less quick to respond to an attempted save. having a sensitive heli in some sense helps you see what you're doing wrong sooner, and teaches you to control more precisely.

also, heavier blade configurations have more momentum, and with more durable material to go with it, you can cause more damage to your heli during a crash with them. for example: a buddy of mine recently pulverized the head on his cp during a chicken dance with plastiblades. after the crash he was left with his tough plastiblades and a not so tough heli that required $36 in parts and a couple hours of wrench time to get airborn. i've seen a few similar crashes, and would argue that he would've only had to replace the blades instead of half the heli if he had woodies on. i'm not trashing on plastiblades, i just think the thought of collateral damage has to be included when you talk about plastiblades. in fact, last week i was wrenching on my heli near my lcd monitor with the motors plugged in (stupid me). when the motor blipped for a second to full throttle, my poor woodies disintigrated on the face of my monitor without scratching it or damaging my shafts. if i had plastiblades on, my monitor would be toast, and my shaft would probably be bent too.