It is impossible to talk about this show without talking about another show: The Amazing Race. Both shows are quite different and I love both.
However The Amazing Race stopped being a race some years ago and now is just "an amazing tour around the world" where the teams are flown from place to place and then compete in challenges.
In the Race Across the World we go back to the roots and the teams are really racing.
I love this show. The teams really need to plan their trip and then they need to race. You get to see places that you wouldn't see otherwise and it is all about the race. Since each team is free to pick the itinerary you will see different routes and styles of travel.
The teams also find jobs here and there to collect additional money to keep traveling. I find those misleading because they are easy to find everywhere and are relatively well paid. That is the unrealistic part of the show. In real live it would have been hard to find those jobs, but at least give us a good look into the life of the locals and many times the racers learn valuable lessons.
Overall both shows complement themselves and are both recommended for anyone that enjoys shows about travel.
Here the pace is quite high and each episode is one leg, where the contestants need to reach a new checkpoint, many miles away from the starting point.