Page content & researching collaboratively taken from io55.net's Lynx page with permission.
There are two Lynx models, and five revisions which only impact system modding.
Models are arranged chronologically.
Model 1 (1989-1991)
The original version of the Lynx. Featuring a generally wider form factor, the Model 1 Lynx is a little bit lower than the Model 2 in certain features, unless you prefer larger systems and don't care about these minor differences - which is completely understandable. To be specific, the Model 1 has shorter battery life (at 4-5 hours), mono instead of stereo audio, and a slightly poorer screen (although neither model's screen is exactly “good” nowadays). Outside of this, the Model 1 and 2 are the same in crucial functionality, such as region lock (both have none), and hacking/modding capability: both models are capable of receiving all important mods and can use flashcarts.
Model 2 (1991-1995)
Released at the relative peak of the Lynx's life, the Model 2 is generally the better system in all ways but form factor (for people who rather larger systems). Featuring an improved battery life (at 5-6) hours, stereo audio, a vaguely better screen, power saving functions (can turn off the backlight - if you hate yourself), and “rubber hand grips”, the Model 2 is a bit nicer and appears to be about as common as the Model 1 within the 2nd hand market. While these changes do make it a slightly better system, it doesn't really matter if one ends up getting the Model 1, as the 2's improvements are pretty minor and will probably be a target for user modding anyways.
While both the Model 1 and Model 2 feature motherboard revisions, these revisions have no impact to external functionality and thus, will only be important to system modding. This section will be expanded and linked into other Lynx modding pages when they have been created. Pages relating to Lynx motherboard revisions have been linked below.