My team uses Expensify, and I have to say, I don’t hate it. The website is full featured, the mobile app is actually pretty good, and you can even just email receipts to an email address and it will parse them out properly the vast majority of the time. Management-wise it has all of the approval chains, grouping, etc that you might expect. The company I work for is only about 50 people and my team is only 10 so I couldn’t say how well it scales, but I imagine unless you have some particularly unique requirements it’d do the job.