I've been shipping world wide for the last 8 years without a problem. Yeah, it's not the fastest, but I've never lost one package, most of them are worth a few grand of product. I'm shipping several times a week with large orders across the USA, Europe, Asia, even Australia.
They have been slower due to the pandemic, but it gets there. Sometimes it's the fault of the country it's going to, as they have certain protocols that must be followed. In the US, it has been slow, most times priority takes 3- 5 days, but it still gets there. I'm sure they are short staffed due pandemic, retirements, etc.
I have no reason to switch, they have been good to me. And it's convenient being close to a Post Office. The cost is much lower and since my international clients pay postage, it really helps them out. Plus, the USPS boxes happen to be the perfect size for my product and fits nicely in all sizes. Hope they keep it up.