I've never heard of Dee's Custom Barrels. Though that in itself doesn't mean they're bad, what makes you want to go with one of those over a more well known brand like Systema, KM, or Prometheus?
My experience has been good with tightbore barrels. I used to own a Systema and now have two Prometheus tightbore barrels.
Honestly, I've had one jam, ever. When I installed the Madbull Shark Hop Up and cranked it "on" all the way, it caused a jam in one of my CA CQBs. I suspect that the fact that I've used only Excel (Which I've heard are smaller than most, but I have nothing but heresay to go on.) and Marui BBs contribute to that fact.