In reply to Dan Cameron (@dancameron).

Our invoicing plug-in needs to interface with Stripe and so I went to WP.org and looked for plug-ins that are tagged with "invoice" and "Stripe", and these are the only two that show up:
Sprout
WP-Invoice

Dan, I'm reluctant to ask this because I suspect you're biased, but given that WP-Invoice has had almost 137,000 downloads compared to 2,500 for Sprout, why should I go with Sprout? I'm especially curious to know what happens if you don't get a larger user base in terms of long-term support.

Thanks