Once I figured out to click the "mark all messages read" I have been happy since.

That was before the final code went out. The final code does the transition automatically so users never see 500 new messages; they see whatever new messages were there at the moment in time the code changed.

Anyway, a typical user will not even notice the new code..... unless he pays attention and realizes he can have 100 new messages waiting but leave after reading only 50 and not miss the other 50 when they come back.