I am a big fan of the FusionInvoice project. I have been using InvoicePlane for a while but moved to FusionInvoice mainly for the multi-currency support and for the continued updates. Support is also extremely reactive and helpful, which for me is super important. The expenses feature is also proving to be very useful, so I am overall very satisfied with it.
Installation is really smooth and the documentation is on point, with the exception of a little hiccup right after you go through it. After installing FusionInvoice and creating an invoice, clicking on the PDF button to export the invoice as PDF would result in the web server throwing an error.