There are multiple problems with the plugin, some that are actual errors and some that appear to be missing features.
1. When client goes to pay invoice with PayPal, an invalid line item error appears. Was not happening previously.
2. Some clients do not receive emailed invoices (not a spam issue either).
3. Some invoices, when marked paid, do not actually get marked paid properly - they still show up as current.
1. No printing or PDF version of invoice
2. No global tax rate - have to set tax for each invoice
Also, although the forum is primarily a user-supported one, one would still expect that the development team would respond to posts in a timely manner. A new version was going to be released on September 30th but there has been silence since then. A quick update would be helpful.
Overall, the plugin works well but the above issues are preventing me from fully using and recommending it.