It took me one, two sessions to adjust the correct length of the cord - not to let the tire bounce after you like crazy and also to fix the double folded flat sling to padded belt with the carabiner in a way, so it does not stretch the belt only in one place, but spreads the pull more evenly. But the rest is OK, the set holds together nicely.
The best part of the training are changing profile of the track - bit of up and down hill and changing surfaces. On concrete parts I can literally lean into he harness, pull more strong, focus on front/midfoot strike and short stride. On dirt roads I whizz by and even push for speed. Whichever way, each session finishes with 200m uphill sprint. Especially for morning sessions, when I may be bit squeezed for time, the tire drag is great. It gets my pulse rate higher - and more quickly, compared to ordinary run. And as am already introducing fartleks, it really gets entertaining. I love the exercise.