When lipo 1st started to get real big in surface rc, there were some studies done on charge rates that showed a relation between higher C charging and lipo cycles (life). There was a definite decrease in lipo cycles as the charge rate was pushed higher and higher.

We been through at least 2 generations of lipo media since then (the 2C safe media and now the 5C capable media). I haven't seen any new testing data and just assuming the new 5C capable lipos have the same cycles vs charge rate character is prob not right. I don't believe Neuenergy or Hyperion would release lipos and say that 5C is ok if cycle life was substantially shotened at the higher charge rates. The older gen lipo when charged at higher C rates would get hot, these new ones from what I'm reading don't get warm at the high C rates. Go to a elec plane based forum - these are the guys that are pushing and driving these changes, they want a lipo back in the air in 10-12mins even if its 10000mah, this is where 5C charging is hot topic.

The biggest time savings is supposed to be in jumping from 1C to 2C. Going from 2C to 3C saves only a few more minutes due to the CC/CV charge routine. And as pointed out, lipo charge rates have outrun charger and PS capabilities. I'm sure we're going to see more powerful chargers coming out, 6 months ago you could harly find a rc oriented 40a PS, now they're easy to find. Some of the high cell counts, large capacity lipos are going to need 650watts or more to charge at 5C. Thats about 2x whats out there today.