Crawler Loaders: too Many Choices

What are the different types of Excavator Crawler Loader available in the market?  I wanted to know this as I wanted to select the best one available to me.  When I logged on to the Internet to do my research, I found that I could choose between a New and Old Crawler models.  That’s confusing!  What made my task more confusing was that there were different makes of the Crawlers.  Just for starters there is John Deere, Caterpillar, and Mitsubishi that top the most recognizable names but that is nowhere near a complete list.   Obviously, I need to do more research before finalizing my decision on which is the right crawler loader for me.