It is simple to understand and the fee suggested is usually correct.
That being said, almost every website o overestimate fees. Usually this is good because transactions do not get stuck, the problem is that people end up paying higher fees.
Personally, I try to see the mempool and look for the smallest fee rate possible to pay to get into the top 1mb jn the mempool . I did an estimator that does that, but It is suggesting slightly higher fees when mempool is empty (need to fix that)
https://bitcoindata.science/plot-your-transaction-in-mempool.html
i switched to using estimaterawfee and looks like it suggests fees closer to what i see on mempool.space