What are the "best" upgrades?

[MSP]

I'd just like to know what people think are the best upgrades. I've gone for DX on Driller, AF on Crusher and RF on Reflex so far.

[luponix]

CHALLENGE MODE: most fun to use in my opinion is Thunderbolt[MX] , most effective Crusher[DX] and Thunderbolt[RT].
SINGLEPLAYER MISSIONS: same as above + any creeper upgrade and MissilePod+ for the light tracking.

[Miasmic]

For CM, Crusher DX
For SP, "best" is pretty subjective. I'm not real sure there is necessarily a best until the last few levels at which point Driller or Crusher DX for the stun lock.

I personally enjoy Impulse Q the most in SP. With Q and Energy Efficiency ++, it's like 3 shots per 1 energy or something like that. Hard to beat that dps efficiency. I think it's also the most engaging and rewarding primary to learn and play with aside from Thunderbolt.

Overall though, Crusher is my favorite primary. It's what sold this game for me.

For other upgrades, I always go speed++ first (even before weapons), for the dodge potential. Then I'll go for Impulse Q, Energy Efficiency, Falcon T or Hunter W, Armor Toughness, Creeper ST, Crusher DX