I started using sticks about 10 years ago and never looked back. I used the Pole Cat ones until last year when they finally broke. I got the Cabelas ones and liked the setup other than the rest. It is rounded and the stock of the gun just floated around in it, very hard to control. I took that head off and replaced it with a V shaped one from a monopod I had laying around, and am very happy with it.
Pros: Very steady rest for long shots or shots where you just need to be a little more precise. Make decent walking sticks as long as you're not really leaning on them. Makes a nice easy spot to lean your gun on when glassing or taking a pee break.
Cons: Get in the way, bang on brush/branches/rocks. Takes time to get them set to ideal height especially in uneven ground.
Likes others have said, if I get into a situation where I know my shots are going to be close or quick, I fold them up and put them in my pack. I pull them out when I'm in longer range area, or if sitting down for a period of time.
All in all, I think they're an invaluable tool.