I have one question on Mercenries. I am a moderately noob warrior

Now,on same level my mage merc does almost 1.5 times damage than the Archer Merc. Few players suggested me to keep Archer Merc due to Hustler & Fatality.
So few thing I want to ask:
1. Does hustler & fatality really helps on high level? With SS & Options, shouldn't a G9 be getting crit shot anyway every second or third hit? Also, increase in damage of crit shot will be applied only when the player & Merc both get crit (according it what it says in skill tab). So does it happen in PvE?(I mean it will be very rare that both land crit at same time). Is the same possible for PvP?
2. How much high level guys actually use Merc while PvP or PK?
3. Finally, all 2-3 players who suggested me to keep Archer as Merc, had Archer Mercs themselves. Can anyone having high level Mage merc can comment, that how effective they find it for lvling up?
I just don't want to mess up and end with a wrong choice whenever I get to high level.



