This place is so hit or miss, unfortunately.
If it's not too crowded and they're staffed up, you'll have a five-star experience. A fun staff running out to your car to take your order, and coming back to deliver delicious juicy burgers, tasty shakes, and fries. A fun way to eat lunch or dinner on a sunny day with your car windows down and music playing.
But I more often have the flipside, one-star experience at this location. They're super crowded and super understaffed. Like last night... it took a long time for someone to get to our car for our order. It then took at least 20 minutes to get our order - which was wrong, and missing items we paid for. (And it wasn't a large order, food for two.) We then had to wait another frustratingly long period of time for someone to come back, and he ran off in the middle of us telling him what we were missing. After yet another long wait, we were about to just drive off when he came back with the rest of our order... which was hastily put together, so that the applesauce had spilled on everything. A sticky mess.
To top it off, the food wasn't up to the standards you hope for when you go to Swensons. The burgers were overcooked, yet somehow the fries were undercooked and basically still spuds. And we didn't even have the ketchup we requested to just smother them with tomato-masking goodness. At least the milkshakes were on point?
Bummer. It's just not worth the risk unless you have a lot of time to spare and you're not starving.