From best to worst:
1. 4g Proxies
2. Residential proxies
3. Dedicated datacenter proxies
4. Shared datacenter proxies
5. Free proxies.
If you have the budget, 4g proxies is the way to go, however they are expensive and if you're managing above let's say 10 accounts, they become quite unsustainable.
If you don't have that kind of money, residential proxies should work fine, as they are less expensive, but in most cases still do pretty well.
Dedicated proxies are always a good idea too, but when it comes to free proxies, well that's just a way to "burn up" all of your accounts.
Hope this helps!