A few things regarding Western. First of all, Ivey AEO is NOT a program. AEO stands for Advanced Entry Option. What this mean, is that at the end of your second year - after pursuing a separate degree of your choice - you have an improved chance of being accepted into the HBA program at Ivey.
Essentially, for the first two years of your undergrad, you study whatever you want. Many people do bmos, political science, and even general science. What I generally hear is two things about your first degree; 1) study something that you are interested in, or 2) study something that offers a return on your investment (grad school chances, employability, etc.) in the off-chance that you are not accepted into the HBA program.
For these two years, you are required to maintain an 80 average, I believe, and any failure to do so will see your AEO revoked. If you successfully maintain that average as well as diverse ECS, your 80 will be more competitive than a non-AEO's 83. Essentially, AEO just lowers the admissions standards and puts your application at the top of the stack for the HBA program.
The HBA program is two years long, allowing you to finish in four years (or five if you would like to complete your original degree as well). It ranks extremely high in Canada (and the world I believe) and is a very sought after degree. What is VERY great about the HBA program is that after HBA1, you can apply to Western Law for a Joint HBA/JD.
Again, just like having AEO, admission standards are much more relaxed. Since HBA is naturally curved to an 80 (which is about the requirement for the HBA/JD program) so all you really need to do is not flunk out and score well on your LSAT. More information can be found on the official webpage. So, if you really want two powerful degrees which are comparable to an MBA/JD I would say go for it. Otherwise, the HBA program is great on its own.
What I will warn you is that although this may be very straight forward - do well in your first two years, enter HBA1 after your second year, apply for HBA/JD after HBA1 and receive an HBA and a JD at the end of your time - it is extremely costly. So you have to factor that in and figure out what you truly want. I did 4 years of an undergrad and will be attending law school. My buddy did 2 years of an undergrad and is now in the joint HBA program. He is spending worlds more money than I am but it suits his interests and law was sort of an after-thought for him.
I think in the end you will spend 6 years? 2 for your BA, 2 for HBA and 3 for JD (your first year of law begins after HBA1 and then you resume HBA2 and 2L at the same time). So, my last thing to say is - what do you want to get out of your undergrad? Is it a stepping stone or is it something to possibly be a stand-alone degree?
Source: I attended Western and have many friends in the HBA and HBA/JD program.
~ all of this is just to keep you informed because a lot of people enter the AEO stream thinking they are already in Ivey ~