Obviously UIET Chandigarh is a much better option. I dont know why some idiots who clear the JEE Advanced examination with a rank around 1k to 5k go for IIT Mandi when they can easily get a college like UIET. I myself is an idiot since I had to use google to know what this UIET is. You ll get a better peer group in UIET because they have more reservation than IIT Mandi and they take admissions on the base of Mains CRL.
I am regretting my decision to take mechanical in IIT Ropar. I could have easily got UIET CSE.
Also, I dont understand why the best teachers and the best phD scholars of India choose an IIT to teach when they have an option of teaching in a great institute like UIET.
Also, I dont understand why a large no. of companies go for recruitment in iit mandi and offer a good package to those students when they can get the students of UIET.
Incase you are getting UIET, go for it. Dont be an idiot like me.
Ignore the placements of IIT Mandi, faculty of IIT Mandi, future opportunities, peer group, research of IIT Mandi, IIT tag and several other things. These things dont matter.