I can't say anything about having "the best", but Lenovo on-site support is good. Standard with some models and an affordable upgrade for others. After using it a few times I really don't want to go back to having to send a device in, so I'll need good reasons to consider a vendor that doesn't offer on-site. Especially since many faults don't make a device totally unusable.

No shipping delays, no not having the device while they "wait for spare parts", no discussions about access to the OS for testing, ...

If you don't have on-site with Lenovo and a service partner locally you apparently can bring/send it directly there and they'll claim the warranty with Lenovo, that might be a good deal as well if you know a trustworthy local shop.