I just beat the second pylon, and my ranking of gems goes something like this:
Lime > Yellow = Red > Green = Cyan > Blue > Orange > Purple
Why? Well, I just love the lime gem, especially at grades 7+ when there is an X% chance to hit 3 (or more) targets, not 2. Yellow is nice, but only at higher grades when there is a better chance of multiple damage. That’s why it ranks below lime: Lime is good at around grade 4, yellow at 6. The creativity of the red gem is nice, and it works wonders in L/R combos. Red is also nice at the end of maps (especially when you add waves) because gems usually have upwards of 500 kills and their damage rockets up 200 points or more when you add the bloodbound gem. I guess I’m not at the point where green becomes terrifically useless – poison is nice when you take a grade 3 and combine it with grade 2s over and over. Cyan is okay, but when monsters become immune, it’s useless. Slowing is more reliable than shocking, but the new slowing formula makes lower levels useless. For example “25% slow” only slows a monster by 12%, which pretty much makes no difference. Orange is only good in traps and in combinations with power gems, and right now (pylon #2) I’m not yet seeing its abilities. Purple had potential, but seeing that at low levels it takes off 0.4 armor levels per hit, and at high levels your gem dealing 153,529 damage will easily ignore an armor level of 500, purple is a piece of junk.
For traps, I buy (for my pathetic excuses for mana farms) O/C gems. Another way to deal lots of damage is to make a grade X poison gem, combine it with grade X-1 poisons over and over again, then put it in a trap – I’ve gotten over 5K poison damage before. Then switch the priority to “random” and you have a pretty solid damage dealer.
What’s your ranking/trap makeup?