[TD-Linux]

This reflects my experience as well. Not only did the B+ add a switching power supply, but there is proper USB power protection and soft-start as well.

Unless GP is referring to the flash problem of the RPi 2.0, which is readily solved by using a case, piece of tape, or an epoxy blob (which I imagine is what will be added to the manufacturing line eventually)

[voltagex_]

What do you mean by soft start?

[TD-Linux]

Many DC devices have capacitors on their power rails. When they are plugged in, they generate a huge current spike as the capacitors charge up (limited only by the resistance and inductance of the capacitors/wires). This is enough to overwhelm the power supply and cause a reset.

The solution is a current limiter of some sort. Sometimes this is as simple as initially powering the USB port through a resistor, watching until the USB voltage gets high enough, then switching over to a direct connection.