The Hapsburg Imperial Family reigned over Belgium for a long time, Belgium did very well most of the time when the Hapsburgs were in charge, Belgium went through her "Golden Age" during the Hapsburg rule. But some people have a bias against the Hapsburgs because of what happened in 1789 and everything related to that period. But without the Hapsburg leadership there would possibly be no Belgium at all. When the United Provinces (that became The Netherlands) revolted from the Spanish Hapsburgs and the Low Countries became the battlefield for the contest between the Catholic and Protestant powers it was the Hapsburgs who made sure that Belgium was retained as a Catholic country, unique and different and did not become a part of the Dutch Republic. I think that if that happened, over the following era Belgium would have been absorbed to become indistinguishable from The Netherlands, in culture, politics and religion.
The spread of the revolution that resulted in the United States of Belgium was because of two causes. There were the republicans who supported the revolutionary ideas of France and wanted to break away from Austria to follow their example but there were also those traditional Catholics who were upset by the policies of the Hapsburg Emperor Joseph II who wanted to bring the Church under closer state control. But, if not for the years of Hapsburg rule both of these very different factions who came together in opposition to the Hapsburgs might have been disappointed, each in a different way. If not for the Hapsburgs Belgium might have not been Catholic at all in the 18th Century but might have become Protestant along with the Dutch as part of the United Provinces. The revolutionaries would not, probably, have been happy with this also since the House of Orange played such a dominant part in the Dutch Republic and even there, already there existed two factions; the republicans and the Orange party that supported becoming a stronger or more strongly united Dutch monarchy. At the same time in The Netherlands there was, therefore, already much division and fighting among themselves between those who wanted to strengthen the House of Orange and those who wanted to get rid of them to become a revolutionary republic. Because of the Hapsburgs, Belgium was a unique place that was spared the same thing and something revolutionaries and Catholics would not have liked.
We can also see what happened in the years when the Hapsburg had been pushed out and Belgium was absorbed by the French Empire of Napoleon. This also caused painful divisions between those who wanted independence and those who wanted to be part of France. I do not think there were many that were still loyal to Austria by that time but probably there were at least a few also. But partly because of 1789 I do not think Belgium was going to be subject to another country for long. Obviously the country did not stay for long united with The Netherlands but even if Belgium had remained a Hapsburg dominion as the Austrian Netherlands, I do not think that would have lasted either because Belgium was too far from Austria and there was the growing power of Germany coming between the two. Perhaps Belgium would have still become an independent kingdom but with a Hapsburg monarch as some of the leaders of the Revolution of 1830 even favored who wanted to give the throne to Archduke Karl. Of course, I am happy with how history unfolded for Belgium, becoming independent with the monarchy of the Coburgs. But we are fortunate I think because the House of Orange and the House of Hapsburg both have been good dynasties that have always tried to do the best for their people.