Very easy to use and functional. Great for travelling or home use. I have even taken them to the gym as I find them better than some of the heavy equipment the gym has. Even though I have dumbbells and barbells at home, I still use my power tubes in preference for many exercises. Weights have the limitation of always being pulled by gravity towards the ground, but by changing the location of the anchors in the total resistance gym, you can push or pull in any direction.
Having handles makes them very easy and comfortable to use, but the downside is they tend to wear out in the same place, so they may not last as long as resistance bands which have no handles. That said I find I can get about 5 years out of a powertube with regular use. I have tried quite a few other brands and haven’t got anywhere near that long out of them.
The resistance levels are a bit random, but this can be overcome by purchasing separately the ultra-light tube, which allows you to set the resistance level with greater precision. The ultra light tube is also great for beginners who may find the light tube too hard for certain exercises like lateral raises. I also prefer to have two full sets of the total resistance gym. This allows me to set up an anchor from both sides for exercises like cross-overs and hero curls, whilst having the same resistance coming from both sides.