A friend of mine bought 3 packs of IB4200's and he was able to make one pack from 3 due to 12 dead cells out of 18. I know this is very unlucky, but I do know it happens with them. Personally i have not had any dead cells.
As far as the poll goes. I have made the switch (for now) to EP, but i still have my sets of IB4200WC's which are not too old if I change my mind.