Keep in mind that many students take 5 years to graduate from Tech because they take advantage of co-op opportunities. Getting paid for three semesters of co-op can offset out-of-state tuition substantially plus you graduate with actual work experience.
Any engineering or computer science major will have to work hard at any school. As @Rdtsmith said, dig deeper. We talked to a number of current students while visiting Tech (random kids - not student ambassadors) and they all felt that, yeah, it is difficult but the school offers numerous opportunities for kids to get help. The concensus was that if you keep up with your classes and take advantage of tutoring, office hours, and whatever you need, you’ll succeed. One kid actually said, “If you don’t do well with all the help they offer then it is probably on you and not the school.” We’ve found the Tech subreddit to be extremely informative, too. Students post questions about profs and classes all the time and it looks like the majority do NOT grade on a curve. The student my son stayed with for a weekend joked that while other schools are famous for grade INflation through curves, Tech is famous for grade DEflation. And Tech admitted 40% females this year so the gender gap is narrowing!
We visited UIUC and were impressed with their program and the students but it didn’t feel like the right fit for DS. He has chosen Tech over UIUC and UT-Austin for a number of reasons. You really do need to look at the programs plus all the extras that are important to you and your student. I don’t think anyone can decide for you if OOS tuition is worth it - it all depends on what you feel is worth your money.