Yeah, it's definitely a grand palace and quite impressive overall. I just found that there are a lot of other castles in France that are very similar but on a smaller scale, so Versailles isn't very unique in that regard. It's also much busier and more crowded and more money and there are some other really cool castles out there. I'm judging it on the overall experience really. It probably doesn't help that it was the last castle that I've been to in France so it seemed a bit repetitive to me. If it was the first then my opinion may be different lol.
The Winter Palace in St Petersburg would be amazing. I haven't seen it myself but hope that you get to see it.