What ohms did you say the clearos where on the 3.7 v PV?
What's an X2 PV? Is that the full name?
EDIT: I assume that's a volt X2 due to your banner.
EDIT AGAIN: Assuming it's the X2 volt 2.6 -2.9 ish ohms
Obviously, I'm not a volt user. I guess it's more "Plug and play" for them.
2.75 ohms at stated 3.6 volts regulation is 4.71273 watts. A bit cool actually. That improves battery life but doesn't always vaporize juice well. Poorly vaporized juice (either too hot or too cold) can give you harsh hits too...besides the nic level and/or flavorings. That's why people love VV...they can adjust it.
If your hits are better after it "warms up" a little, and then get worse if you set it down for a while that could be an indication that its too cool.
Also clean the contacts just to be sure you're not picking up any additional resistance from oxidation/gunk on the threads.
Just some thoughts.