Fly26:
what level of equipment is being used to sweep the seabed?
Basically, two things. They are listening for the flight recorder sonar pinger and also using active sonar, including side scan.
One problem with sonar is that the coverage tends to be fan shaped. The deeper the water, the broader a path they can cover on the bottom. The waters where contact was lost aren't very deep. So the strips of bottom covered per pass won't be very wide. On the positive side, the nature of the sea in the search area rules out things like thermoclines and other phenomena that could blind sonar.
If by some chance MH370 made it East to the Philippines or West of Sumatra, there are some deep drenches and rougher bottom terrain to deal with.