Dual File Manager is the only one I've tried that allows me to view files held in an encrypted zip, which is how I store confidential (but not secret) information, such as web site passwords, etc.
Having used dual-panel file managers for many years (Norton Commander, Volkov Commander, Total Commander, Midnight Commander, etc.) I've also got used to the dual-panel paradigm.
For occasional forays into the system folders I have to use Root Explorer so DFM obviously isn't perfect, but it the one that gets most use on my phone.