Singapore is rather boring compared to HK, with its more edgy and exciting life. But I will say Singapore is better for raising kids, a little more family friendly. So if you are single or married without kids/or already have grown kids, maybe HK is better. But if the kids are still of school age, Singapore would be preferable.
I'll say this, as unpleasantly hot and humid as HK is now till September, it doesn't last all year. The cooler fall and winter months is a lot more bearable. Singapore in contrast is like this year-round.
Why some people find Dubai appealing is a mystery to me as well. I heard a number of expats praise it to no end. But when I was there, I wasn't particularly impressed with the place. I can understand folks moving there for work reasons. But as a place to live? With an arid bone dry climate that is like a furnace in the summer? No thanks.