Definitely easier to use than siphon ad pails.
I’m giving it a 4 because I may be using it wrong, per se.
By the time I finish filtering half of my gravel (30 gallon aquarium), the tank is still left with, about, 10″ of water. I then have to refill the tank before cleaning the other half of the gravel.

If that is expected, then it is not written or shown anywhere.

It’s very easy to use, and rather efficient for changing the water. However, the gravel tube is very short, very hard for me to filter gravel without wetting my hands. In addition, I used it many times so far, yet never managed to filter even half of the gravel before a third of water of my 20 gallon aquarium tank was gone.

I have been using Pythons of various lengths for at least 25 years now, and have never encountered the slightest problem. The oldest one I currently use is about 15 years old and still going strong. Basically, the Python is an essential piece of equipment, especially for those having several largish (100g and up) tanks, as it make routine water changes a breeze, and therefore, one tends to perform this task far more frequently than in the old days of lugging water about (which might be why see more large aquariums now). Changing water is an essential task; no matter how well planted, no matter how well filtered, without routine water changes, nitrate buildup will eventually kill fish (there are ion exchange filter media available, but they quickly become more expensive than the Python’s initial cost, plus water changes assure that any other toxins are kept in check). Unlike the previous reviewer, I do mine single handed, without problem; and given that my mechanical skills might be considered to be good were I, say, a large gerbil, it is a very easy item to operate. I cannot recommend it highly enough, nor imagine keeping the number of tanks that I do (actually, I couldn’t) without having a Python.—–rick