The modern toaster ovens are pretty amazing, this one also has the convection fan. I can fit a pretty large oblong pan in there. No sheets of cookies or loaves of bread though! Sometimes it is good to be low carb.
There are some differences and there are times when there are some distinct advantages and I believe I will continue to have one even after I have an oven again. For one, I would just take it outside in the summer, set it up on a cooler with a large cutting board for a surface, plug into the outside outlet and could bake things without heating up the inside of the house.
I've found that I prefer doing some things on top the stove, like pot roast I'd rather simmer than bake. Same thing with corned beef (one of the hubby's favorites). LOL meatloaf though -- that's probably best in the toaster oven.
I also prefer to do some things out on the grill. I like playing with fire and charcoal, gas would be convenient but we go the charcoal route. I always prefer to do my leg of lamb on the grill. Sometimes we will do just a small portion of something on the grill, but often we will cook ahead for several meals. So maybe we would be having steak that night but also cooking pork spare ribs or burgers for the next day. You can even do take home/you cook pizzas -- lovely crust.