Three stars means I liked it. Which I did. It is a nice wholesome, sentimental, mildly melodramatic adventure in the same tradition as Little Lord Fauntleroy, or the Five Little Peppers, or What Katy Did.
The story is definitely of its time. In some ways that's a whole lot of fun. I really quite enjoy the bildungsroman aspect of these stories, where a child becomes a better character through exposure to good examples, plenty of fresh air and a modicum of hardship and danger. The Lady Bountiful chapter near the end when she comes back and rewards everyone who helped her in her trials and tribulations is just pure wish fulfillment fun. Also I always like that late Victorian convention of including an epilogue that shows what happens to all the characters after the book ends.
Its a very comforting world, where the good are rewarded and the bad are punished, and with some reasonable perseverence it is possible to gather happily around the warm family hearth of the rose garlanded ... well you know the conventions. Of course in some ways its also kind of silly. If I had to actually live with those conventions I wouldn't find them nearly as charming - distance helps me to regard this stuff with fondness.
The characters are vividly drawn, but simplistic. The wicked uncle is bad because.... well because we need a villain. He's just introduced at the outset as someone the family lawyer says was a disappointment to his family - someone who drinks and keeps bad company - nuff said. Later its suggested he may have had a head injury as a child.
The wholesome family with whom Sydney's guardian places her is known to be wholeseome because... well because a charming well bred person on the transatlantic liner said they were the right sort. And so they prove to be. Its very much a world where people are what they appear to be on the surface. Their manners and their clothing and their speech tell you what you need to know.
There are other examples of this same sentimental tradition that are better remembered, I think because they have some element that makes them a little bit exceptional. The Secret Garden for example because of the garden, the deep love of nature. Sydney's Fortune doesn't quite rise to the same level. But its still fun to read both on its own terms and as example of what was once a big category of juvenile fiction.
I also just loved that the copy I read had a sticker in the front showing that it had been awarded to a student at the United Methodist Sunday school in 1913 "for regular attendance and good behavior." Just like the story itself, a whiff of air from a different, past world.