Beam cars do just fine if they are set up properly. It's like anything else.. A properly built beam set up will do better than a poorly built A-arm. The amount of travel you end up with is only part of the equation. Things like bump steer (or preferably the lack of it) and how much downward travel vs. upward travel you have available are important, too. I've seen plenty of cars with lots of travel, but if your frame is 2 inches underground at full bump, it isn't helpful.