i'm glad they are avalible that way now ,saves me buying 2 sets of bearings,
i think its a great idea ,for me i always rebalance with all gears and keyways on,as well as when you are mocking up your motor it makes life a breeze.
i don't now what they are worth in comarison too 2 sets of bearings,but i will look at it very soon once again.i say if your motors agart and the price is reasonable it won't hurt too have a extra steel backed bearing set in there.