Customization capability out of the box is somewhat limited with regards to customizing the loan application -- any customizations that you want to be included in the risk analysis require the Turnkey team stepping in. Using a custom loan agreement template also is extra (theirs is probably not adequate for use as a licensed lender in the US). That being said, the Turnkey team has been extraordinarily helpful in helping roll out customizations and working with us on timelines and unique customizations that we requested. Would have liked integrations w/ cloud-based accounting software out of the box -- not critically important, but I expect more orgs that want to utilize true cloud-based lending platforms probably don't want to be tethered to the traditional on-computer Quickbooks.
After using for a while I have a few other caveats: default portfolio exports are limited, reporting page is very limited (no way to run various reports), automatic loan document generation does not apply to restructured loans for some reason (fixed now), payment integrations only work with automatic scheduled payments (you cannot simply run a payment -- you have to go to the payment processor itself, manually run the payment, then manually log in Turnkey).
Last caveat was issues w/ technical help. Was having problems running ACH payments manually through Turnkey: the system appears to allow this (and even says that it *will* use the payment integration). We would submit the payment in Turnkey and it would register a successful payment, but was never uploading the ACH payment to the processor. After going back and forth in circles for weeks the tech help eventually said that processing payments manually just isn't supported (and used a graphic showing that manual card payments weren't supported -- not what I was trying to do). Frustrating but not a deal breaker. Review collected by and hosted on G2.com.