Also bear in mind a few other things -
1) they each have hundreds, if not thousands of customers, so on the balance of probabilities, there will be a small percentage of people who weren't happy with their service, and they'll be the ones who shout the loudest, compared to the vast majority who were happy.
2) a good 90% of problems that people have with importing aren't actually the fault of the broker, but rather the people and companies they've used along the way. Brokers get just as frustrated as their customers when things go wrong.
3) Common sense suggests that businesses who shaft their customers don't last long, and the import brokering game has many 'fly-by-night' operators. The fact that both companies have been around for a while should tell you something.