Very interesting and useful post Lesli!
I used ModernBill years ago and it was decent - but just not flexible or user friendly enough at the time. I use custom systems for all my commerce now, but I still found the post quite informative.
Originally Posted by Lesli
I tried using ModernBill (now being rebranded as Parallels Plesk Billing) for two years, and finally switched away to WHMCS. WHMCS is secure and reliable, has a great feature set, adds features with every major release (and doesn't break the old ones), simpler to configure than ModernBill, and costs less - both to buy initially, and to renew support.