I have used Wise for small ($ hundreds) transactions for both business and personal use. It is fine, albeit the limitations on cash withdrawals can be annoying.

For business I do relatively regular transfers (USD 20-40k to CAD at a time). I don't use my Canadian bank's FX service, as it borders on highway robbery. Instead I use www.KnightsbridgeFX.com. Lately I have been regularly comparing KnightsbridgeFX rates to what Wise can quote (fx middle rate + % fee). Each and every time on a sum of USD 20-40k the difference is < USD 35 one way or the other. I have been tempted to switch my business accounts to Wise entirely, but have not pulled the trigger yet.