It's your choice man, and how you make your armor sets and skills. I personally have both, but yeah, until I made it to G rank all I used was elemental charge blade (except dragon, but we're getting an elemental dragon charge blade soon in terms of Fatalis). What I would do is specifically hit my phial explosions in areas I know are weak (especially to element), like Rathalos' head or Teostra's back legs. So yeah dude, I say for for whatever suits you best. However, keep in mind the strongest charge blades do have elements, like Ceadues Regalia, with 1080 raw damage and 310 water damage.
The major deciding factor in my opinion is the armor/set you use. Although frankly it seems most GAFers lean towards impact phials for since you can easily increase their damage and have the benefit of KO, but that's your choice.
For example, I have two sets. One I use for elemental blades and one I use for impact blades.
For impact, I have the following skills:
Challenger +2 (Attack up XL and Critical Eye +3 when a monster is angry)
Artillery Novice (I also eat for Felyne Bombardier so it stacks to get Artillery God).
Honed Blade (Attack up L and Sharpness +1)
Razor Sharp
Element Attack Up
For elemental charge blades, I use a basic all around set:
Mind's Eye
Sharpness +1
Weakness Exploit (for them weak spots)
Speed Sharpening
Tremor Resistance
Critical Eye +1
(Any other five slot skill)
As you can see, it all depends on what you make of everything and personal preference.
If you want elemental, go elemental, if you want impact, go impact
-Alternis
