IK it provides very high fire power with relative light weight, but the problem is that the recoil from a charged shot is enough to knock the reticle off the lock-on to the enemy, and you have to aim again before you could use your powers.
Also am I the only one that always charge before shooting an arc pistol?
The Arc Pistol gives you three choices.
#1: Headshot = dead. No need to fire a power at them anyways.
#2: Use the pistol to prime FE/TB, in which case, if you aim for a low bodyshot, the recoil doesn't pull you out of lock-on, leaving you free to fire a power immediately.
#3: Fire the power before you release the trigger.
And yes, you should always be charging before shooting. The only time I don't is for swarmers.
Who needs sound effects anyway? I can headshot things far away with pinpoint accuracy and still have my CDs at a level where I can create combos at will. Something the claymore can't even dream about doing. Yes, I don't like the claymore outside of 1-2 classes. 
inb4CDsareoverrated
I'm the same. My Krogans get the Claymore, occasionally some other soldiers. That's it. I love it on them, but I have no desire to use it on anything else. I just wish I could keep pistol amps in stock...