#34 Really like the use of wood grain in lettering. Like the transition from charred to wood.
The font is too soft and rounded, I think. Most of the better designs have masculine fonts and/or ALL CAPS. I think it's the "building block" aspect of the product that needs a blocky font. Tagline needs a tougher font as well, maybe in red?
I like smoky wisps but maybe not two on each letter?
#40 and #41 both excellent. Took me a while to see shadowing on #40. #39 also excellent. I'll have to think about the shadowing for a while.
#44 Like the flame in the D a lot. What is idea of circular arc swooping from top? It may be stronger if gradation were more horizontal. It could ragged or uneven, but largely horizontal.
I like the tagline font of your #44 better than what is in 39/40.