General user experience is very awkward, it just simply doesn't work as well as many of it's competitors (Xero, Kashflow, Quickbooks Online etc). It strikes me that the very basic of it's double entry & how the data interacts with itself is just build wrongly from the ground up, you can't do basic things such as adding a credit note for part of an invoice (instead it must be written off as a bad debt, even if it isn't). Doing certain things feels like wading through very difficult treacle, things that are done very easily on it's competitors platforms.
Aside from that, the integrations are quite limited, but that isn't surprising considering how it positions itself in the market is in direct competition to anyone who places them self as a cloud integration specialist who can help with this kind of thing. That is a feature which severely limits itself as any kind of long-term growing business solution.
For full disclosure, I'm an accountant by trade and FreeAgent is positioning itself to be the software that removes businesses from needing one, but which will result in business paying more tax, doing things wrongly and not managing themselves properly. I therefore fundamentally disagree with FreeAgent's course. Review collected by and hosted on G2.com.