Hi, Matt. L3 has been around for years and is very well regarded. It's easy to use with several presets. I have not heard of Pure Limit. I'd have to read up on it. My guess is that, like most limiters, they do very close to the same thing. Before investing in L3, there is a page of each of its manuals you can download and look through at https://www.waves.com/downloads/manuals. It shows you how they actually work so you can skip their flashy promotions.
John