There really isn't a difference in the product lines from the double convoluted style or sleeve style.
The only thing that is obvious is how the top and bottom plates are attached.
Firestone uses a crimped steel where airlift uses a press formed plate.
Also, when it comes to buying and installing these "kits" you should know a few things first.
Both companies will sell you a 2500# bag kit, this is a smaller set of bags which to allow for leveling or lifting, will actually stiffen the suspension due to the amount of air required. In all cases it is best to remove the overload springs and maybe one to two leafs from the pack.
A better option, but is more work is a Inside the rail system, this way you can use a larger diameter bag which requires less pressure.
Although I am not associated with this company, I have used the products on several occasions. They are made in the USA in Arizona and I have visited their plant on several occasions. This site is very informative if you look around, they build all of their own kits, the bags are firestone rubber but they build their own hats, they also make bags with removable ends and such.
http://www.airbagit.com/v/vspfiles/pages/TowKits_PAGE.html
In closing, You don't need an on-board air system. Most people I know, after a few trips know the required amount of air in the bags. They then will air out the system when not in use. This is very common for guys who buy the bolt in 2500# kit that you see everywhere. If you buy a kit and install your self, it is very easy to do. DO NOT CONNECT THE BAGS TOGETHER. Connecting or Teeing the air lines of both bags is very dangerous. It will allow the air to transfer from one bag to the other causing severe body roll.
A most basic bag kit with brackets should be around $300. A compressor and paddle kit will run another 200.
2012 Kodiak 300BHSL Ultimate with Fall Edition Package
2003 Ford Excursion V10 Sold!!
2005 Ford Excursion 6.0L Diesel