Yes of course they are still available. I'm on my 3rd gen Chuckler and have called in over 30 bulls with it in the last 3 years. Did quite well with the previous Chucklers as well! How is it for comparison? Couldn't tell ya. You know what they say, "if it ain't broke".
They have been out of stock when I checked the past few months. I do not have a Chuckler but they seem like a quality tube.
As an alternative you could look at one of the Phelps tubes or a RM Bully Bull Extreme. If you can call it probably doesn't matter what tube you carry, they will all work well.