Wise is good, but you have to be careful when using multiple banks and transferring money between yourself and other users. It is possible to get into a situation where your account goes negative, and in that case, more scrutiny is placed on incoming transactions. This is not necessarily Wise's fault, but it can create a situation where money gets held up in transit for as much as a week while everything processes.

An example to make it clear how this can happen without any kind of fraud:

My fiancé added $200 from his bank to his Wise account for the first time and transferred it to me. From all appearances, it had cleared and was in my Wise balance. I spent that money. A week or so later I logged in to find my account had gone negative because the original transaction did not clear my fiancé's bank. It was a new transaction to an online service and was flagged and denied on their end. This resulted in me having a negative balance. None of this is abnormal or exclusive to Wise, it's a result of how bank transfers work.

What did screw me up was that I did not realize that my transfer of money into my account to settle the negative balance would be subject to extra scrutiny and withheld until it was completely clear. I had transferred $2000 to cover the shortage and money I needed for bills that had to be transferred to my non-US bank. So for about a week, I did not have access to that money while everything was sorted out.

Again, this is not a structural failure on Wise's part. But the information you need to understand how to avoid this situation is not terribly obvious in the app, and their (totally understandable) policies around extra vetting when accounts are negative can result in money being tied up longer than usual.