Good design, poor support and payment transparency.
While the overall functionality of TooLost was great (uploads, analytics, etc.) the support was underwhelming. There were numerous times I reached out with an issue only to get a copy-pasted response that didn’t directly address my issue. Additionally there were, what I believe to be, issues with their royalty payouts. I used TooLost for multiple years in tandem with another distributor. In those years I received a total payout that was roughly 10% of what I was paid using the other distributor, even though the streams and sales were comparable across the numerous releases. I personally believe there is an issue with their payouts, not necessarily something malicious, but definitely an error somewhere.