Yeah, it is real time. Its low/medium/high priority suggestions are some of the most accurate that I have found, so if you are looking for a site to just tell you a fee to use, then it's probably your best bet. They seem to correspond to somewhere around 1.2 MB from the tip, 0.8 MB from the tip, and 0.3 MB from the tip, respectively.

Having said all that, I still think there is no real substitution for learning how to read the mempool yourself and decide where you want your transaction to do. Fee estimators generally only estimate based on a current snapshot of the mempool, and do not take in to account the recent mempool trend. If I want to be in the next block or two and the mempool is rapidly filling, then I might want to aim 0.1 MB or even less from the tip. If, on the other hand, there are very few transactions being broadcast at the moment, then I might be happy to go 1 MB or more from the tip. At the moment, that difference is between 80 sats/vbyte and 15 sats/vbyte, but could be even more pronounced.