Mortars are ok on rush. I only use them to counter-mortar people. Things to be aware of. You don't get hitmarkers so you never know when you hit and when you miss. You can cycle between explosive rounds and smoke rounds. You will be visible on the map (looks like a bomb symbol) and a single mortar will kill you while you are in your mortaring state. Expect lots of kill assists more than actual kills.
I rarely switch modes. The only gun I do switch is the g3. I have yet to use a weapon in burst fire. If I recall, few weapons have the burst function to begin with.
I'm a little ho-hum on the PDWs in the game so far. In most cases, I'd rather use a shotgun or the actual weapon set of the class. I would use them on recon but I never play recon. I do get the PDW-R in two levels and it's supposedly pretty good so my mind might change.
