Candace, good question.
1. Yes, typically SMT LEDs can cover further range / distance than PTH (plated through hole) LEDs. Related, that's why you typically see cameras with many more PTH LEDs than cameras with SMTs. An IR camera with SMTs may have only 2, 4 or 8 while one with PTHs routinely have 24 or more.
2. The other claimed benefit is, as you say, better heat management. My understanding is that since the heat of the SMTs do not radiate out as much it is easier to manage heat.
In terms of a study, we have tested many cameras with both types. In general, the cameras with SMTs have better image quality / more even FoVs but that might also be because they are from 'better' cameras overall.
The other issue would be life time / reliability and that we do not have definitive stats. That being said, most of the mid to high end IR cameras have moved to SMT and you generally see PTH on real low end cameras.
I'm in Atlanta with lots of Georgia Tech connections. I asked a friend to use one of their light spectrum analyzers. Epistar emitted 30-35% more photons at 850nm. From an OEM (which we are) standpoint they are also about 30% more expensive at the chip level but that's 40 cents to 52 cents so... doesn't matter.
Nice to meet you. You all do a great job here. Best in the industry in my opinion.
Give me a few more months and I'll show you what we're doing. Very different, very focused, very neat.