"I have heard the flavor is different. Can you elaborate?"
Good question! The short answer is that it's all about temperature control.
The biggest difference is that most vape pens don't have much heating control and run much hotter than the Firefly. The coils in the vape pens generally run red hot which is around 1500F. The overall temp of the coil is lowered when the coil is submerged in a liquid, but all that extra heat goes into the liquid (even the part you're not consuming right now) and actually starts to break it down and release the more volatile components like terpenes (the molecules that make up flavor https://en.wikipedia.org/wiki/Terpene). These more volatile components can be quite fragile and when exposed to too much heat actually break down and decompose.
The Firefly in concentrates mode runs at 500F. This is temp is high enough that all of the active ingredients will vaporize and produce great vapor and not so high that it will decompose the terpenes. So the Firefly is better and more efficient at releasing the active ingredients without degrading the more delicate molecules like the terpenes.
Sasha made a great explanation about the extra volatile heat, but I think one of the most phenomenal things about vaping with a FireFly 2 is taste.
One of the most amazing things we have today is our high profile cannabis, with these ridiculous strains of our current day ganja there are overwhelming beautiful terpenes packed with flavor!
These terpenes hold a lot of the THC and smell as well as the taste of the plant. Whilst using the FireFly 2 you can enjoy the full flavor profile of the cannabis you are inhaling. Getting the subtle flavor notes of a plant you've never tasted before has never been so satisfying, the lower temps of 150-210 taste like bliss.
As your temperature rises higher you will be able to taste every flavor that's hidden inside that gem of a plant. As well as all of the medicinal benefits of the cannabinoids at those lower levels of heat.