I do use it myself for SciFi (mostly for Traveller) and I like it. Of course, the number of available styles is not as overwhelming as the ones available for fantasy, but there are some good options.
One thing worth noting: for Sci-Fi you definitely want the highest tier, which includes Cosmographer and all the annuals.
The page for Cosmographer shows a few styles: https://www.profantasy.com/products/cos3_examples.asp
And here’s a few deckplan exampless on a classic Traveller style: https://www.profantasy.com/products/cos3_deckplans.asp
As for the annuals, there’s this post on the forum with a small screenshot/thumbnail for each issue in most annuals: https://forum.profantasy.com/discussion/10366/cartographers-annual-all-the-issues-linked-in-one-place
Finally, there’s this Youtube Playlist with a few of the mapping sessions that focused on Sci-Fi styles: https://youtube.com/playlist?list=PLrFvDl9qgYgsCVt58a41H3rcDjsAc4P4h






Glad I could help.
One more thing: The official forum is a place full of very nice and helpful people.