I've been using SPO for a few months now and it's been working great for my business; auto-sending PO's to vendors means I never have to worry about forgetting to send it = peace of mind. I've had a couple of questions along the way and support has alway been quick and helpful. I would recommend this app.
It is a good app, and does the job. However not the greatest for layout and design, it needs to be able to be customised to suit your branding and fonts adjusted. It is very very basic PO form, would love for it to improve. I have requested a few times now if i can edit or change style but nothing yet!