The lack of the front shock on the base st1 was a deal breaker for me, I remember riding the stromer and after about 30 mins my wrists were a little sore. Granted I purposely rode the st1 over every bump possible, a and in the grass trying to simulate how riding would feel in my neck of the woods. There are a few st1 owners on this site that will surely chime in.
Hi MarcD! The Stromer electric bikes feel heavier to me and while it's nice to have some cool options in their control interface (and I'm sure the ST2 will have even more) I loved the IZIP E3 Dash because it was simple. The bike has throttle, assist, similar balanced weight distribution and is much lighter (~50lbs vs. ~62lbs)... though possibly not as cool looking with the external battery design.
The Dash is a newer design than the ST1 Platinum or Elite and it uses three sensors (torque, cadence and speed) which makes it very responsive and smooth. The Stromer bikes use a torque sensor (which is still good) but less smooth and refined.
As with Aubrizzle, I also prefer the suspension fork but you can get the ST1 Platinum with it if you want. I'd go even further and consider suspension fork plus a suspension seat post like the Thudbuster or Body Float.
I have the ST1 Platinum. I rationalized the Platinum just for the suspension over the Elite. I still prefer the Stromer over the Dash just for the "stealth" factor, very important to me. I have not ridden the Dash so I can't compare the actual bikes.
I do have a Thudbuster, but interested in the Float as an even better way of helping w/sore backside.