For starters, much greater significance will be placed on your ability to lead competently and confidently.
This means you'll be required to speak before your class, give drill, and issue orders. You'll be required to plan and conduct several missions and taskings.
Teaching reflects this difference. You'll be given lessons on receiving/issuing orders, public speaking, etc. Phase 1 is longer than BMQ -- 17 weeks to 13 (exact week count subject to constant change). You'll also be in the training system significantly longer -- most NCM's are done the system within about a year. As an OCdt, you can expect that to at least double, much more if you're ROTP or UTPNCM.