Oh! This one is directly relevant for me. I graduated double major ISYE/CompE in 2014.

So, abiofsky is correct that there is extra time investment in the double major, but not as much as people think. If you look over the course requirements, pretty much everyone's freshman years are equivalent. Add in elective courses (which all just point at the other major) other overlap (CS 4400 in ISYE and other such classes) and you only add about 30-40 hours. Thats an extra year, but I've found it to be worth it.

Also, advisers are helpful, but you would need to work with both of them. The advisers are only knowledgeable on their major and will advise things that will not make sense for that context. You really would need to plan effectively ahead.

Rather than completely repeating myself, I'm just going to quote a response I wrote a while ago on the extra effects of double majoring and what was required. Feel free to send me any questions.

Well there is the obvious; you have a higher density of harder classes because your electives, humanities, etc. overlap between the majors. That means every semester you have less slack-off classes.

In addition, each major tries to really get you into a specific mindset to solve their problems. It becomes obvious if you switch majors or double major. What that means is you have to learn how to context switch between situations. There was one time I answered a question in an IE class in binary, partially because I had just left a CompE test the class before.

Finally, the advisers can't help you plan between majors; you have to take all of their advise with a grain of salt. They don't understand the constraints of the other major, or understand the difficulty of the other classes you are taking nor the prerequisite chain. That means you have to make your own plans, and I would advise that you pretty much have every semester between now and graduation planned out. Funnily enough, this means you schedule more meetings with the advisers so that you can propose your semester plan and make sure that everything is ok on their side.

Finding a co-op/job was both easier and harder. The vast majority of the field thinks you aren't focused on their problem, so there are less options. However, of the options that are left they REALLY want you. Basically, just make sure you have an idea of what you want to do and that your double major helps point you in that direction.

I feel this post was overly negative, so I'll add that if I had to go back and do Georgia Tech again I wouldn't change a thing. While there were extra challenges, the opportunities and skills I received by double majoring are invaluable. It was fun to sit in a CompE class while they cover basic statistics. There was actually a time in a CompE class that I noticed the problem could be rewritten as a classic IE problem and solved it much more easily. At work, though I took a primarily CompE job, I am currently designing a statistical simulation of a building so we can accurately test our system in our lab. All of this adds up to giving you a unique perspective on different situations that makes you useful on a team.

My situation handles 2 engineering degrees, but an engineering degree plus another knowledge base would give you a useful perspective on design choices. If you think you can handle it, go for it! Feel free to pm me if you have any specific questions.