As I stated, money talks and if you are talking significant money at Booth and end up with nothing at Kellogg...then your decision is easy IMO. If Kellogg ends up being fairly close in gift then its time to make a tough decision.
I am not doing the entrepreneurship path, and I dont think there is a real difference in the reputation of the entrepreneurship of the two schools. Both have solid programs in it, I know Steel is doing some entrepreneurship stuff at Kellogg (choose it over MIT for entrepreneurship too) so he might be worth PMing. Also I dont think this is a path that requires a reputation like many other fields. You will use the same skills as a GM, you will just happen to own the company. If you have a great idea and manage it properly then you will be succesful no matter which school you choose. Yes Kellogg does have a better rep in healthcare but once again you are planning to start your own business not recruit for healthcare jobs then it probably isnt that big of a selling point for you.
One selling point of Kellogg's ent program is the paid internship they put you up for. They will actually set you up with start-up companies that apply so they are screened by the school. Then they pay you better than what start ups typically pay. Kellogg does have the larger selection of electives (overall and entrepreneurship courses). Boh have clubs, I know kellogg has both an entrepreneurship club and a family business club (both might be of interest to you) and I am sure Booth also has a club. Both are going to have some sort of business plan competition (I think steel is working on one right now).
For me the decision is more based on fit. Unfortunately admitted students weekends overlap so you cant attend both. You will enjoy you life at both schools but they do have different personalities. Its hard to see the difference in many ways since students at both schools love them. Things to look at, where do you want to live and what type of community experience are you looking for. The vast majority of Kellogg students live within a mile of the school and each other...this creates an incredibly tight knit community. You can live downtown if you want but it seems like you would miss out on some of the community experience.
I wont say Kellogg's alumni are as close to the school as Tuck but I can tell you reaching out to alums from many years ago, they still feel a strong attachment to the school and community. I have had conversations that go beyond school and they will talk about local bars or things in evanston they did with their friends. I have heard from friends at various other schools about the involvement of alums, and I think Kellogg is one of the strongest in this areas...there is a huge push to involve alums more too. Beyond reaching out to them for the jobs, money, and stuff like that...they are trying to keep them in the fold. The spending on alumni relations has gone up drastically over the last few years and the school realizes their best ambassadors are alums. I know classmates who worked for alums and it is one of the reasons they ended up here.
If you have a significant other moving with you, the JV at Kellogg is a huge sellling point for many couples here. I think this is part of the reason Kellogg has one of the highest percentages of students bringing a significant other with them. I know my wife has made some of the best friends she has ever had here over the last 9 months...trust me when you are slammed with school and recruiting it is nice for them to have that group of people who understands what they are going through. I enjoy having that too since it helps them realize that they are not the only ones dealing with all that stress and time apart. They also do a lot of fun things together and we do a lot of stuff as couples with our friends too.
Either way you go, you are going to have a blast for the next few years. The schools have a lot in common and are great places. I know personally I had schools ranked before I got decisions but promised myself since they were all top 5's if one gave me a lot more money thats where I would go. I got admitted to my #1 and got money so my decision was easy. The easiest decision for you probably will be if Kellogg gives you nothing or way more money. If they end up being very close, you should try to remember what your gut was telling you before you got admits. I know I liked all my schools but definitely felt a stronger pull to Kellogg than the others.
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Kellogg Class of 2010...still active and willing to help. However, I do not do profile reviews, don't offer predictions on chances and am far to busy to review essays, so save the energy of writing me a PM seeking help for these. If I don't respond to a PM that is not one of the previously mentioned trash can destined messages, please don't take it personally I get so many messages I have a hard to responding to most. The more interesting, compelling, or humorous you message the more likely I am to respond.