The Modlite PL350 is the latest/greatest new emitter and illumination system for handguns (and long guns should you so choose) that has graced the market.
The light has been a long time in development and offers a few things others like the X300U do not.
Exterior charging of the 18350 style battery cells is one such advantage, the ability to ‘plug your gun in’ or at least the light unattached is one that allows for more proactive power management since it is fewer steps to change and check power.
The amount of steps in a process does matter to how likely we are to do that process, making it a plug in puts it on the same difficulty of charging your phone rather than the disassembly process of a battery change out that was standard on lights.
The second advantage is the interchangeable emitter heads, making the light configurable based upon need. The PL350 can best be thought of as a control body with selectable emitters, the PLHv2 and the OKW being their native ones. While most users will probably choose a PLHv2 for a pistol light, if one is used on a long gun an OKW may make sense or using the increased candela of the OKW around bright headlights and other interfering light sources depending upon the users environment.
It’s a versatile addition, works with a few holsters like Safarilands, and has a few more already out in the wild from companies like PHLster.
Do you need it if you already have an X300 or TLR-1? Probably not.
Is is certainly worth considering as a next light or if you are looking to acquire lights of certain performance requirements and easy of user? Absolutely.