Was Gutman really all that bad?

I think Gutman was very pragmatic and realised that Spade could be an asset to him later on, he did mention he had hoped he would accompany him to Istanbul for example. Probably also just showing how much money he actually has that he can spare $1,000 and not think much of it.

I feel like Gutman was portrayed as a man who was very dangerous when crossed, but not particularly emotional or quick to violence. He was pretty ruthless in sacrificing Wilmer for example, and in having the ship captain murdered when it meant advancing his own needs.

Yes. Gutman is a fiendish man, driven by appetites and whims. He is both obsessive (the search for the bird) and capricious (his flip way of handing people over or letting them have $1,000).

But, he's also cunning. Sam says that he was meant to be bribed with the money. It's likely that Gutman thought that by paying Sam the $1,000, he'd put Sam into "cahoots" in the eyes of the law. In other words, by paying Sam, Gutman might have thought Sam wouldn't go to the cops for fear that he'd be implicated in the operations, too. Little did Gutman know that Sam was far more honest than he (Gutman) believed.

That's a black mark on him, too. He operates assuming everybody else is crooked and evil. A better mind wouldn't assume that, but one of evil nature assumes the worst of those around him, as well.

Finally, he talks a good game, and he might have a certain cunning practicality to him - intelligent - but his actions are all sinister. He's a liar, a cheat, a betrayer, disloyal, and murderous. He will go to any lengths to own what amounts to a bauble.

In short: this is a bad person.