Having used an loved my Compak for a few years now, if you're not in a hurry and have the money to spend on a new Forte, I'd forgo the convenience of the Forte and wait for a good deal on the K10.
It's Peter's fault....
No, no, no. You stepped too close to the edge. It's not my fault you were so easy to push over it.
So, can someone explain to me why the 68mm conical burr on the K10 is preferred to the 83mm flat burr the K8?
It may be one of those online things, where if you repeat it long enough and loud enough people believe it to be true. Then, they can't admit that they spent too much and of course, the shots taste better.
Or, and I'm only thinking out loud - the shape of the burr is more relevant than the diameter; perhaps the conical cuts the particles differently than the flat burr; perhaps there is more cutting area on the conical as the cutting area is more vertical. All guesses. But please, start repeating them online as though some guru has said it... it'll be 'true' by this time next year.