As far as infrastructure and faculty is considered which is better?
I think iiitdm can be preferred?

iiit kancheepuram obviously

Well.. think of IIITM Gwalior... IIITDM Kanchipuram is a very new institute and has a poor infrastructure.... check this Facebook page for pics of IIITM Gwalior... Also, IIITDm had very poor placements this year... on the other hand, IIITM Gwalior is the first established IIIT in india in 1997 and has awesome placements even this year with highest package offer reaching 18 lakh per annum...

www.facebook.com/iiitmg