Akti is a straight-forward app with plenty to offer. It's not concerned with being the prettiest-looking, but makes up for that by being very efficient. It allows me to create a quote, turn that quote into a project and then into an invoice. A big time gain for me.
The flexibility (adding fields, multilingualism, ...) is one of Akti's strongest assets. And the price is pretty low if you take its potential into account.
There's some work to do on the design part (esthetics), but that might just be me...