OCR is On Campus Recruiting.
The school can tell from their database whether you were a PT MBA or FT MBA graduate, but when you are looking for a job yrs later, it wouldn't really matter whether you did your MBA PT or FT.
I am pretty sure EMBA is distinctively different from regular PT or FT MBA degree (meaning it's not the same piece of paper. A FT or PT MBA student typically lists just MBA on the resume but EMBA students have to put EMBA on the resume)
Why does it cost more? I guess it depends on the program (if it does cost more) because like you said it covers for weekend expenses, but some programs have international experiences and other programs (i.e. - Tuck EMBA apparently travels to different Fortune 500 companies and hold seminars or classes on foreign locations)
Experience and classes? A lot of bschools put PT and FT MBA students in same class (especially for electives) but EMBA students only take courses with EMBA students because they operate on different calendar. So it should be a different experience.
Which one is better? Again, it's based on individual need. If you are relatively young (even in early 30's), PT MBA is probably better because courses will be more relevant to your needs and also your classmates will be around your age, etc. If you are older and you are in charge of running a segment of your business (and you are almost always in office), EMBA is probably better for similar reasons.