it is for the later Sammies, at least. I use CWM on my S4, but that's because it's the only one I seem to be able to get working.
idk about the ATT and VZW variants bricking, but their bootloaders are locked to begin with. so, you're limited to Sprint, T-Mo and other non-US variants.
I personally have learned to live with no expandable storage, but miss the replaceable battery since they limit the life you can use the handset for, efficiently. unless you disassemble the device to replace the battery.