Which is better, Resist Critical Rate (RCR) or Resist Critical Damage (RCDI)?
First lets know how to obtain both attributes (or options) and what items can have that attributes. Take note that when your Honor ranked-up, you'll also gain RCR and RCDI through Titles (check Achievement).
Items that can have or you can put RCR and RCDI are: PETS (through Pet Training), BIKES (Upgrade using RCR or RCDI scrolls), and Epaulets of Guardian (Archridium and Palladium).
Resist Critical Rate is the rate of resistance that lower the opponent's chances to do Critical Damage towards you. The higher the resistance rate, the lower the chance the opponent do Critical Damage.
Example:
YOU = 20% RCR
OPPONENT = 70%/70% CRI
When the opponent attack, his chances to do critical damage will be lowered up to 50% (low chance)
Resist Critical Damage Increase, on the other hand, is the rate of resistance that lower the Critical Damage dealt by the opponents made with his attack towards you.
Example:
YOU = 20% RCDI
OPPONENT = 70%/70% CRI and 300% CDI
When the opponent attack, his chances to do critical damage is still 70% (means high chance) but the Critical Damage it dealt will be lowered by 20% (300% -20% = 280%)
Things to Consider if you're planning to have RCR and RCDI in pets and/.or bikes.
1. Price - RCR is more expensive than RCDI.
2. You will sacrifice your Damage to gain more RCR and RCDI.
Again, this is based on my own personal knowledge and opinion.