I have this stroller:
Pet Gear Happy Trails Blue Pet Stroller for cats and dogs with free shipping
It was a gift, I didn't pick it out- I honestly don't use it enough to justify the expense of buying one myself.
The pros of this one are that it is big inside- it has fit three dogs before just fine- they all have room to lay down and move around. I also like having the space underneath- I use to take the dogs outlet shopping with me in the stroller and it was nice having the space to put bags and stuff.
The cons are that it is pretty heavy and takes up a lot of space- I have seen the new lightweight versions of these in the store and would probably get that one next time if I was buying my own, especially if it was just going to be for one or two small dogs (as the lighweight one is also smaller). I also don't like the mesh opening on top- the sun beats in there- I usually end up covering it with a small blanket- the whole front and back are mesh, so there is still plenty of ventilation and space for them to see out- the top is pretty useless anyway, since its not like they are going to be looking out that hole.
Here is the lightweight version I was talking about
Pet Gear Travel Lite Pet Stroller, Dog Stroller, and Cat Stroller with free shipping
I don't know how either one of these would be navigating harsh terrain or anything but they navigated around the outlet centers well!