Had a sit-down dinner here a couple months back and was pleased. Good atmosphere and very good fish, but the highlight is definitely the Friday Fish Fry. I live nearby, so at least once a month we get a take-out order. Their portions are healthy enough that it feeds 2 of us. Milwaukee is probably the greatest fish fry city in the world, and River Lane may very well have the best fish fry in Milwaukee.
Bear in mind, for general meals, River Lane is a bit pricey. The reason we prefer take-out is because you run up a big bill in a hurry here. But if you're close or just looking for Friday Fish Fry, this is definitely the best choice in the area.