In many ways, Lando Calrissian is a mirror image of Han Solo, a parallel universe version of our favorite smuggler. By the end of the film, however, the differences between these two men only give us a greater appreciation of Han than ever before.
At first, Lando seems more respectable than Han. Although he used to be a smuggler back in the day (he was even the original owner of the Millennium Falcon), he's since turned away from a life of crime to become a political leader in Cloud City. It's a tough job running a shoestring operation like this, sure, but it's a whole lot better than smuggling illegal goods for giant slug creatures.
Ultimately, Lando gets hamstrung by these responsibilities, forced to betray our heroes to protect his city:
LEIA: Do you think that after what you did to Han we're going to trust you?
LANDO: I had no choice.
This is a genuinely tough decision and, if we were in Lando's shoes, we don't know if we'd have acted differently. However, here's one thing we do know for sure: Han wouldn't. They could've bribed him with a million Kyber Crystals if they wanted to, but Han would never have betrayed his friends to the Empire.
In other words, appearances can be deceiving. Han the scoundrel is actually a respectable man, while Lando the respectable man is actually a scoundrel. Although Lando does eventually double-double-cross the Empire—and will go on to become a valuable member of the Rebel Alliance in Return of the Jedi—he'll have a long way to go on his road to redemption.