I'm glad GOG was finally able to get this game back on the store shelves. This game has many things that its sequels (and two knockoffs) never included. My personal favorite is getting into a ship and ejecting just before it crashes into my enemies.
It's a good game on it's own merits, and we wouldn't have its Flatout 2 without it, but this game can feel a bit lacking when compared to the sequel. If you're new to the series, then go with Flatout 2. If you want some extra maps and to see where the series started, then go with Flatout 1.