I travelled to Asansol by NDLS-HWW from NDLS and returned back by Poorva express, both trains are having LBH coaches but I didn't see any significant difference from previous coaches (in term of speed & comfort), on the other side I found that Toilet window in LBH coaches are completed sealed so there was not no ventilation in toilets which makes unhygienic & gives nasty smell and unbearable to stand in it.