Hey, sorry I never got back to you on this.
For one thing, the size and weight of the Spheroid. The Heron's kinda heavy but it does really shine on the Ti X since the weight balances out better for me.
The draw is another big part. Funny thing is I used to love a real airy draw but to me the Sphero has the closest pull to an actual analog. It's damned near perfect... not too tight and not too airy. Even closing off the air slot on the Heron the inhale just isn't the same. I almost use the Herons akin to sitting home with a fine cigar. Something where I'm not worried so much about the draw but the flavor and everything else.
For day to day life I love my Spheroids to death.
Lastly is it's just so much easier to deal with the coil and wick on Spheroid. I haven't tried the Heron without the cotton topper but it's a pain to get to the wick and coil without having to break down the whole base. It's still miles above my experience with the KFL+. Friggin KFL had to be totally dismantled every other freaking tank for me...
ETA: Just got my v1 Spheroid in the mail and was not expecting a wire inside

Is there any way to upgrade the base to a v2 type connection? It looks like the v2 510 pin would fit.