So I cant answer the Kellogg question, but I can provide some color on Booth...
* First, in terms of classes: by and large you will have access to the same professors teaching the same classes as the FT program, so on paper anyway, the education is the same as FT program. In that sense, the PT Booth program is pretty stellar.
* Booth has grade non disclosure; i dont know if this matters to you at all, but its something unique to the program (Kellogg does not, but does generally subscribe to teh concept of a "gentleman's B")
* Third, booth allows you to take as many classes as you like as a PT student whereas Kellogg has historically (again, double check, things change) limited you to two courses. This has an interesting effect at Booth; it means that in very practical terms theres really nothing stopping someone from applying to the PT program, quitting their job, taking a full load of classes, and graduating in two years. For that reason, many of the FT view the PT program as a cheap backdoor into what is otherwise a highly selective school. I admit, I am among those - but I also admit, had I not been admitted FT, this would have been exactly what I would have done. It used be even worse (or better depending on your POV): PT students used to be able to sign up for FT classes (meaning during the day, on campus, etc) with no preference given to FT students. (The inverse was also true, FT students could sign up for evening classes with the same preference given to PT students). So, it wasn't uncommon for PT students to attend "FT" classes. While it is still technically true that you can do this, now preference is given to your home program; thus, FT students get 'first dibs' at FT classes, PT students 'first dibs' at PT ones. While you can still graduate in 2 years, it makes it a little more difficult to do so or a bit more challenging to get all the classes you want.
* This may have changed, but Booth allows you to interview on campus for FT positions provided you have completed a certain number of courses (12 if I recall) and attended some very basic interview training (couple of hours). Kellogg, if memory serves me right, requires you to have a note from your current employer saying you are allowed to participate in campus recruiting. That might be a meaningful issue, it might not be. From the perspective of a FT student, its meaningful: the FT recruiting pool at Chicago has hundreds of PT students suddenly added it to it. This doesn't generally engender a lot of love.
* Fifth, to the best of my knowledge, neither Kellogg nor Chicago allow PT students to interview for on-campus internship positions. That doesnt mean you cant get an internship, just that you cant eat up a regular interview slot.
* From an academics and rigor point of view, I think there's little question Booth stands out, but frankly, this matters little once you graduate.
* As you may have gathered, FT students generally dislike PT students, and while friendships certainly exist (some of my best friends were PT), I'd say its more of an arms-length relationship for most people. I don't know how this is at Kellogg, but I imagine its not very different.
* You will be locked out of a lot of the FT student clubs; in part because this is just an issue of fairness - there are FT consulting clubs and PT consulting clubs for instance - in part because of what I mentioned before. The PT student clubs, im told, are not the same quality as the FT ones in that the FT ones get corporate sponsors, more attention from recruiters, etc. I dont' know how big of a deal that really is in the end, but I thought it telling that it was a frequent occurrence that PT students would try to join FT student clubs (even when PT equivalents existed).
* I know of several people who complain of the PT career services as being quite lame compared to FT, and frankly there's no extra bandwidth with career services to go see PT students.
That said, if it were me and I were doing it over, I'd pick Booth for PT; really for three reasons (assuming these three differentiators still exist): 1) grade non disclosure, 2) ability to take more classes and finish faster if you want 3) comparatively easier and more liberal FT recruiting policy compared to Kellogg.
As to the poets and quants thing, not having it read it, I cant critique it directly, but I can tell you Booth has all manners of companies coming to campus - banks, strategy consultancies, biotech, pharma, energy, PE, VC, IM, corporate finance, general management, CPGs, high tech firms, think tanks, economic consultancies, non profit, federal, educational, manufacturing companies, real estate development firms, foreign investments, bla bla... theres hundreds and hundreds of options coming out of either Booth or Kellogg...
(Note: you should validate my claims, things change, I graduated in 2009)