Welcome to the forum Trond.
I'll try and give some feedback to your issues.
Using "Styles" (menu "Edit -> Styles…") should fix the problems you're having with text formatting. Set-up a character style for how you want the text formatted (e.g. font/size/etc.), then set-up a paragraph style based on
the character style but with the paragraph formatting you want (e.g. line spacing), then apply the paragraph style to the text.
If some formatting changes are later applied by accident then just re-apply the style to fix it. (The "direct" formatting features should only really be used for minor "emergency" formatting issues, and getting used to using styles can really speed things up when you want big formatting changes so they're worth the little bit extra effort to learn.)
Printing from Scribus is a well-known problem and the advice usually given is to not print directly
from Scribus but to print from a PDF reader (such as Acrobat) instead. If you create the PDF first you can then check it properly before printing; think of it as a final proof check. (You only need something like bookbinder if you have special printing requirements which you probably won't have if you're using a normal desktop printer.)
Scribus was designed to create documents that would be sent to a printshop so the "extra" PDF export step is just part of the normal production process. (And once the file is in PDF form you don't need to open Scribus to print it again, so that's a bonus).
(My personal preference would be for Scribus to lose printing functionality - except preview - altogether but I can't see that happening any time soon. I.e. The developers could leave printing to the PDF readers and concentrate on more important things.)
I've been using Scribus for some years now and, while it does have a few "interesting features" (ahem, bugs), it's generally fine and does what's needed without much fuss. (It's certainly better than anything else that's free. It's difficult to argue with the price!) As with any software you just need to get used to using it.
You don't need to take my word for it though, see http://wiki.scribus.net/canvas/Success_stories
for more than ten years' worth of testimonials.
I really hope your experience hasn't put you - and your daughter - off using Scribus in the future. It really is very good once you realise the best way to use it.