I was using Toolbox some time and found it inconvenient. This flying button time after time covers required area, so i have to move it from one place to another. I've found notification panel quick launch is much more convenient. It doesn't cover screen and requires the same amount of finger actions to launch the app.
Samsung Galaxy S4 SHV-E330S: Optimus ROM (TW 4.4.2) & Kernel. CPU OC 2.7GHz, GPU OC 645MHz, non-KNOX bootloader, UHD/SM/360 Camera.
Samsung Galaxy S4 GT-I9500: Optimus ROM (TW 4.4.2), Perseus Kernel. CPU No-OC, GPU OC 700MHz, non-KNOX bootloader.
Past models: Samsung Galaxy SIII SHV-E210K & GT-I9300, Samsung Galaxy SII GT-I9100.