I work on my bikes frequently and I wanted to fill in some gaps and replace a few things. The overall quality of the tools is good with some variability. For example, the hex wrenches are only OK and it didn't come with any t-handle wrenches or torque wrenches (which would increase the price). I tallied up the list prices of the tools at about $400 so it's a great value if you are starting from scratch. If you've already got a collection of tools, you would need to evaluate whether this kit is worth it.
I have used Park Tools' GSC-1 Gearclean brush for years, and it does a good job on chains, chainrings and cassettes. The GSC-4 is more specific to the cassette - it's wider, and the bristles are angled and contoured for that single purpose, so it's more efficient for that purpose.
I did have to figure out the best way to use it. The angle makes it "one-way" (hold in your right hand while standing behind the wheel). If the wheel is off the bike, it will only work on the push. On the pull, the cassette will simply spin. And I do prefer to use it with the wheel off, since otherwise the chain is in the way. Bottom line - if your cassette is dirty, this brush together with the right cleaner/degreaser will quickly get it clean.
I had high expectations of the Park Ratcheting Torque Wrench, and was disappointed to find it didn't meet my expectations. The overall quality wasn't high. There were stickers applied to the stem to depict conversions, and were starting to peel off. The torque readout was difficult to see. I had to really look carefully to adjust the setting to the needed torque. The worst part was the notification that it gave that the torque setting had been reached. Rather than giving a satisfying click, the ratchet head merely pivots slightly. At lower torque settings, this is nearly imperceptible.
Now that I'm using tubeless tires, I've found it almost impossible to remove from one from the wheel rim to insert a tube if emergency puncture on the road. So I've got one of those tubeless tire plug tools, but just in case I need to add sealant, I bought this valve core remover, to add sealant through the valve. I haven't had to use it yet, and I plan to try it out at home, just to be sure I will be familiar with the process if I get stuck on the road. I don't expect there will be any issue with removing and reinserting the valve, though.
