Silver Lake is the best map, but the gap to other maps is not as big as some think. There are many cases where Silver Lake is not the best choice.
- Outdoor Areas: Just as good as Silver Lake, in my opinion. If you want to start with a partner zoo, this is usually the best choice, as you can pick up a second partner zoo on the ground and get an early upgrade. Alternatively, you can sometimes just pick up the partner zoo from the ground and support a project. If you want to play a lot of large animals, this map is also even more excellent than usual.
- Rescue Station: Also an S-tier map, just as Silver Lake and Outdoor Areas. If you know that you can dig something valuable with your first build action, I'd recommend this. It can enable a round 1 project, which gives you a lot of tempo, or at least let you dig an animal which gives you two or even three valuable tags. Also great for flocking.
- Research Institute: A bit weaker than the others, but the map ability which lets you ignore one requirement can enable a lot of nutty starts, especially when want to release something like a Muscox or a Bison which is usually locked behind a requirement. On this map, you can also play the New Zealand Fur Seal without upgrading animals (it's possible in Round 1), which gives you an early worker.
- Ice Cream Parlor: Definitely the weakest amongst all the listed maps, but if you can unlock all the income very early, this is very viable. This usually includes at least one sponsor building (the play-sponsor bonus on the ground is very helpful here), something like Engineer or an animal with Posturing is also very good.
All other maps are basically never as good as Silver Lake.
Now the problem is of course that you don't get to see your hand before picking a map, at least per the original rules. Therefore, on BGA, picking Silver Lake is usually the best and safest choice. But if you play at home with a physical copy, many people have house-ruled the map selection, allowing you to see the display and your hand before choosing. In that case, Silver Lake should not automatically be the default option.