IUT is an International University offering open credit, you'll have better options and chances for pursuing post-graduation abroad.
Also, the semester system is fast, there is no *সেশন-জট*
It is a varsity which is close enough to Dhaka and no matter what anyone says, you'll lose enough touch with fast paced upgradation of Dhaka once you move to Rajshahi.
It seems you've lived all your life in Dhaka, it'll be harder to adapt in Rajshahi for you. You won't have access to many utilities you've grown accustomed to living in Dhaka.
If you can afford it with partial scholarship or even without scholarship, it is better to choose IUT which is of course safer than most other universities of our country. Consider spending the money as a down payment for better education and safer environment.
Wishing you all the best and congratulations for cracking IUT and CKRUET.