After a high which lasts 4-6 hours, the comedown is mild, although some experience slight headaches and nausea. Wikipedia says few people can use BZP daily for any length of time but I would completely contradict that -- just expect to feel bad the day after you stop. Tolerance also increases pretty quickly and it's not abnormal to reach doses of 400mg or more.
Due to its recreational use, its posession and sale is restricted or illegal in several countries. In the UK, it recently became a graded class C drug which is a huge shame because when I tried it in 2008, it was still readily available.