Are you meaning for undergraduate studies? No one can tell the job placement in you home country. Non us have difficulty with jobs here without a MS degree from the little I know, the work visas are limited. You are subject first to OPT/CPT.
What is confusing exactly about these colleges? The first 3 You mention are similar in that they are all large state colleges with students taking a wide varieties of majors. IIT is a bit different in that it is a private tech school and focus is on STEM majors. Aside from that there is a difference in location. It think IIT has more international students and is in an urban setting. uVA is hardest to get an admit and has the strongest students overall academically. But all should have strong engineering students. UMD and Purdue both have strong engineering especially, look closer at those.