The short version
Bang Pu is the coastward edge of Samut Prakan, where industrial land, older communities, mangrove and seaside recreation sit beyond the dense Bangkok core. It suits someone whose work is south of the city and who prefers a slower, more open setting. It is a poor fit for a central commute.
The atmosphere
The Bang Pu recreation area and the road towards the coast give the district a different horizon from inner Bangkok. The industrial landscape is just as important. Housing varies from local streets to estates and apartments near the transport corridor. Do not confuse a sea breeze at the weekend with an easy weekday route.
Getting around
The BTS reaches Kheha, and buses and cars continue towards the coast and industrial areas. The station is useful for the northern part of the district; the outer parts need road transport. If you work shifts, test the route outside office hours.
Verdict
Bang Pu is a lifestyle choice only for someone comfortable with distance. I would choose it for coastal air, local scale and a south eastern job, while accepting limited car free mobility and a long trip to the centre.