They are not fair competitors at all, they are two different classes of scopes. The Rattler 35 competes directly with the Hogster 35. Both those optics have 384x288 17 micron thermal sensors and the Super Hogster is 384x288 at 12 microns and it shows. The Rattler 35 is also only 2.2x compared to the 3x of the Super Hogster. They are very different. I consider the Rattler an excellent entry level thermal, one of the best, but the Super Hogster has mid-range thermal image quality.
I like them both but the $625 that separates them in cost is noticeable and the 3x and superior image quality of the Super Hogster makes it much more suitable for longer range shooting over 100-125+ yards. While the Rattler 35 is a excellent out to 100 yards and capable at 175-200, it's going to struggle at the longer ranges and the image quality is going to greatly degrade when you zoom up compared to the Super Hogster. The Super Hogster has an ID range that is also much better. I don't say any of this to bash the Rattler, if you're not looking for longer range shooting and it's in your price range, I believe it's a bargain, but it's in a different class of scopes than the Super Hogster.
I know it's long but Hans and I discussed all this in depth a few weeks ago because there is so much confusion out there on these optics. If you want, you can skip to 7:00 and it's where we begin discussing the optics directly.