I only have experience with the small Air Ranger, but I can tell you that it is very nice knife for the price. Some people knock the Made in Taiwan aspect of these knives, but a Taiwanese assembly machine can do just as good a job as a domestic one, and apparently a lot cheaper.
The Air Ranger gets my vote for best knife around $40 that I know of. It just edges out the Kershaw Vapor in the "solid blade for peanuts" category. I like the checkered aluminum handle, which is confortable and grippy. Nothing fancy or goofy on this knife, nobody trying to reinvent the wheel. Just a great handle, a good blade shape, and a very solid liner lock; all made with quality materials.
There is a new smaller International called the LTR which looks pretty cool.