We have the two devices in our household now and they are so different it would be unfair to compare them really. The FM is rock solid with nothing to break, it's braindead to use, so easy any newbee can get it without needing any introduction, it's compact, nicely designed, has incredible (initial) battery life and on top of that it's bloody cheap... but the pros stop here.
For the FM cons: it's fixed temperature (although properly regulated), taste degrades pretty fast (a good deal of conduction going on) and for now we have no clue what the material used are and the air intake path is not completely sealed... I also suspect that one of the two batteries will degrade pretty fast as it's sitting very close to the bowl.
Now the FW (2.1) is a completely different beast! I'm not specially a wood-loving guy (I much prefer living trees than dead ones) but I have to admit the FW is a nicely made object. It's compact too but bigger than the FM. It's made of (as far as I'm aware) safe materials, the air and vapor paths are free from electronics, there is glass inside...
But it's a tricky device seriously. I wouldn't recommend it to a newbee and I don't pass it around, it's my very own personal vaporizer. There is a learning curve, as you have to get used to the heating element power (ie how fast it heats up and how fast it decays when you draw) and basically you end up with a fluctuating temperature point that swings up and down around the vaporization temperature range. So you kinda get the whole spectrum at once, or can focus on a narrower band (if you are skilled!)
That plus the clear convection transfer method and the glass path makes the FW taste pretty good and strong, that is... until some tiny spots start to blacken inside the load and start compromising the whole taste. For now I got the impression this happens more with tiny particles, leading me to think a coarser grind would be better.
At first I was very frustrated by the FW but it excels at small/micro loads and if you want a "quick fix" it allows you to get there pretty fast (more 40 secs than 20 secs though) I use it when I'm in a hurry and can't afford to do a 20+ minutes session with my Ascent (or when it's charging) So it definitely fills one of my needs.
But it's hard to fully extract the load and the battery capacity is not meant to do long sessions. Also you need to be careful not to overheat the device. I'm a bit affraid it will char with time... Ah and due to the NiMh used, charging is very long too. That should conclude the cons.
Different needs, different solutions?
EDIT: Ah and on both the vapor path is very short, but on the FW the vapor can get uncomfortably hot, I had to extend the drawing stem by pluging a spare Ascent straw in the provided silicone tubing.