I've used them both. The IB conditioner is an instant conditioner, the IB conditioning balm is meant to be used a little longer and the treatment is more intense than the regular conditioner. It's a really good product.
yes, i agree with pebbles, the intensive blends conditioner is just a regular conditioner but the conditioning balm is more like a mask or deep conditioning treatment. i love both.
I don't think it would be too heavy. I would use the regular conditioner for conditioning washes, and use the balm as a deep conditioning treatment as stated on the bottle.