In this troper's mind, since I have seen the series from season 1 to 3, I noticed that out of the three, it is the third season where the quality of the show that is so far the best.
While I would consider myself to be a casual fan, there are a few scenes I couldn't stomach in seasons 1-2 because they were so... well dubious. The most prominent examples of the episode would be Alexander the Great vs Atilla the Hun, and Centurion vs Rajput. They not only used a siege weapon against a more conventional weapon (Ballista vs Ax, Scorpion vs the Chakram seriously?), but also failed to account the psychology of each different warrior.
But with season 3, I noticed I enjoyed it far more than previous seasons, to the point I only watch episodes from season 3. The inclusion of Mack from Future Weapons replacing Geiger in the show made it more enjoyable 'cuz he ain't simply the computer drone given a rather lame justification, he's an actual SEAL and actually gives opinions on weapons and psychology that are at least a little bit more believable. Along with the fact that they are now categorizing weapons with each other better (especially siege weapons), it greatly improved how much I am able to enjoy the show.
In short, I believe while it is a better idea to see all the way from seasons 1 - 3, I believe it maybe a good idea to skip to season 3 for other viewers due to the immense reworking that the series gone through, since its that much better. Keep in mind though, you may be a little irked that again, American warriors seem to be on a winning streak, but that alone should not hinder your ability to enjoy the show.