There is a lot of info if you search the posts on BU, but I'll answer your specific questions.
-BU is not laid back. Lazy yes, very lazy, but not laid back. Lazy students that don't attend class, come unprepared for labs/procedures, and whine about test questions they answered incorrectly. It's very stressful and cut-throat, and students are always trying to get unfair advantages over their classmates. Clinical instructors disappear during appointments to go across the street for coffee, or go to the faculty lounge to surf the internet. Staff who do minimal work, at minimum pace. It's always an adventure searching the building for your instructor, while your patient waits for over 30 minutes with all that crap in his mouth.
-yes, many students do not finish their work on time and end up staying weeks/months after graduation to finish their quotas. This has nothing to do with teaching, but everything to do with the shortage of patients at the school, and the overcrowded facilities, which is worsened by students wasting resources by booking fake appointments.
-your remarks about APEX and finding jobs with mentors is just another BU advertising slogan. It also reveals the crony/nepotism culture at the school. When 85% of your DMD students have parents who are dentists, and your APEX mentor is a relative or close family friend, they usually help you find work upon graduation. You have to have a big head to believe a first or 2nd year dental student-assistant-stranger can honestly impress an established practicing dentist enough to get a job offer. If a mentor gives his student a job offer, it has nothing to do with what happened during APEX.
My problem with APEX is mainly with the fact that every student has extremely different experiences and different graders. There is nothing uniform about it, so by definition it is an academic farce, but happens to be the most heavily weighted courses your first 2 years.
Imagine your first 3 years of dental school, with no vacation time except for Christmas. It's brutal. No vacation between years in the summer, but if you manipulate the system a little, you get 5 months of vacation in your first 2 years, and get an automatic "A." I'm sure those students think very highly of the APEX program.
the positive: some people like this sort of system, with all the games and personal favors. If you know you are not very bright, and are a terrible student, and will be a terrible dentist, BU is perfect for you. You just have to work the system, and expect to specialize in some field that doen't require much manual dexterity like ortho, perio, or oral pathology.
My advice is the same as earlier: pass on BU this year, re-apply to other schools next year. At the very least, request to defer for 1 year, and see if you can apply to other schools and if you don't get in to any, you still have the BU acceptance. Don't let your immediate financial concerns influence your decision because if you go to BU, it will cost over $400,000 plus interest after 4 years, double the cost of a state school. Once you start at BU, there is no turning back, since you're in debt 6 figues and it's impossible to transfer to a different school in dentistry.
If you do find yourself at BU, keep a very low profile, don't stand out in any way, good or bad. Play along with the status quo, don't be an individual; think of it as 4 years of acting school. If you want an insurance policy, convert to Judaism, change your last name so the last 3 letters are "-man," and wear a yamika from day 1 of school.