Both are very good and reputed colleges but NIT Warangal and Agartala are considered as equivalent to an IIT and therefore if you have the opportunity to get there it will be really good. 

BITS Hyderabad is also a very good college and it's really progressing and campus placements are also very good but it comes under the category of a tier 2 college. 

So depending on the college reputation you should go for NIT Warangal and if you are considering place only then you can choose any of them.