Latest Answer: Hi Susheel, This was a great concern that i had when i booked a flat in sunderbans. In terms of construction quality VGN is far superior. and we enquired about the same to jains they said the outerstructure is been used solid blocks which is been manufactured by them.for the innerwalls they use hollow blocks.If you go to any metros ecpecially in bangalore i have seen all the aprtments using only hollow blocks and no bricks are used for constrcution. Advantages: costeffective for the builder the overall weight of the building is reduced. bricks are always better than blocks as blocks absorbs temprature. bricks are cool. In foreign countries only hollow block is used.just put a google search and you will see a lot of advantages/disadvantages Dont bother we donot have a say. i am satisfying myself .