I too have been experiencing extreme smoothness with the Firefly. I was a bit worried when I ordered about that but at this point the hits are so smooth that I am continually surprised by how much vapor comes out of me. I've been hitting by a spotlight because I was convinced at first that I wasn't getting any vapor, but I'm getting plenty.
The only time I have "felt the heat" from a hit is if I REALLY go for it or if I push the heat button a second time too quickly.
The first hit from a cold start can be a bit underwhelming, for me. But with a little technique I've been able to just hit it once from a cold start and feel medicated enough for social situations. But I tend to go for two or three since I can hit it so quickly again without making as big a smell as two or three hits will cause by me when using the Ascent.
I still love my Ascent, especially for nighttime knockouts through water and for sharing with friends, but the Firefly is definitely my go-to portable with the Ascent as its backup. And I have no qualms with shelling out more money for an external charger and a couple extra batteries.
The Firefly sure ain't cheap, but it is goddamn luxurious and worth every penny, in my opinion. I fucking love this thing. I just wish I had chosen the red one...
I am also getting better results with a little tamping down!