How do you guys handle trip attacks?

Imagine a combat situation like this.

A: "[cool exposition] I trip B!"

B: " [cool exposition] I get up and hit A!"

If B can just stylishly get up and attack in the same action after being knocked down, it won't take A long to realize that any sort of trip is just a completely wasted action when he could have been doing damage instead.

But on the other hand, getting up and hitting somebody in the same action is totally in keeping with the kinds of stunts people do in this game. And even having the 'get up and attack' cost 4 shots instead of three isn't nearly worth the 3 shots that A spent to put B on the ground for an instant.

Something similar occurs with most grapples- there are very few holds (that is, none) that a victim can't just attack anyway while held in, with some good exposition.

Depends on who you are fighting against I guess.

With the trip against a mook, what are you really wanting to achieve? If you want to just knock him on the floor for a couple of seconds then...well he's going to get up.

But the difference is you get to decide how you take him out.

Don't want to damage/kill him? Got a good result? - then the trip easily could send him off his feet falling backwards ass first into a conveniently placed barrel where he is stuck until the end of the fight. Or more simply, he falls on his head and is knocked out for the rest of the fight.

Against a non-mook bad guy?

Well again, it depends on what you wish to achieve.

Usually there are more than on PC trying to attack the big bad - in this case then tripping him so it costs an extra shot (or do a stunt at -3, maybe 2 extra shots before he can act) then that might be just the time that your spell casting buddy needs to pull off a "banish" spell, or your high damage bruiser needs to run over from dealing with mooks to stomp on the guys head.

Remember, if you're not going for an effect that would do more damage, or give you some sort of advantage later on then there's no need to apply stunt penalty either.

i.e you can do more than just trip someone in one go if you were thinking you were only tripping him to set up your next attack

for example

I punch mook in face, it hits, he goes down

is the same as

I trip the guy off his feet, he lands hard and as he flips himself back up I jump spin kick him in the head knocking him into a box of rotting veg.

As they both have the same effect - 1 mook out - then there's no extra penalty. Plus, you add the descriptive fun of the scene.

Here's how I generlly handle it.

Making a trip attack, but dealing no damage?
Enemy has to spend a shot or two getting up and not attacking. Useful to buy time against opponents with high Toughness or immunity to your damage type. If it was a one-on-one fight, it might even take three shots for them to get up, letting you stall for a Fu refresh or something.
Or, you might rule that the next player to attack the tripped target (assuming he doesn't get up before then) gets a +3 AV bonus, like aiming, because of the disadvantaged enemy.

Making a trip attack, with some damage?
Call it a stunt, for the usual -2, with any of the above.

Making a trip attack, making someone fall off somewhere precarious (or into a bark chipper)?
Call it a stunt (unless it's a mook), and let the outcome be what it may. Even a huge fall will only badly injure a named character, so that might be a fine way of having the villain escape to come back in a later session. Dangerous environments should be dangerous, otherwise they're not that much different from anywhere else.

Queex has some good ideas, and I'd probably go with the essence of those for the most part. I might require some sort of "athletics check" to allow a character to kip up to their feet for a reduced shot cost or something, instead of the full, what, 3 shots? Something along those lines, and there may still be a penalty.

My general reckoning is just to treat it as another stunt. If it's successful, the opponent has to spend a shot or two getting back up. Simple.