I think they are pretty comparable. Sugar free monster and reg monster are basically the same
Both taste like the feces of someone living on a diet exclusively of smarties and sweet-tarts.
Rockstar Blue Can
No Fear Blue Label
Crunk White Can
Sugar Free Red Bull
Celsius any version
Full Throttle silver can
Nos silver can
All taste substantially better.
For taste I'd rank them as:
Rockstar = Celcius > Redbull > Full Throttle = Nos > Crunk = No Fear
For effectiveness (all inclusive, not just caffeine/serving):
Redbull > Celcius > Crunk = Rockstar = Nos = Full Throttle > No Fear
Redbull is the MOST widely available, followed by Rockstar and Celcius, Nos, Crunk and No Fear vary.
Rockstar and Amp both make a low-carb (3g sugar/serving IIRC) lemonade that isn't terrible but also isn't sugar free.
Also Monster contains glucose as an ingredient, which is what sugar digests into, no? So how is it technically sugar free?