Aaron Seigo is a long-time KDE developer and the one that has been working on the (rather unsuccessful, albeit evidently they will have new hardware soon...) KDE Spark/Vivaldi tablet. He's not a fan of the Ubuntu Phone nor Canonical's marketing claims.
He feels what Canonical is now pushing with their platform is what KDE developers have been promoting for years already with KDE Plasma for the cross-device spectrum. Canonical is now also relying upon Qt and QML. Siego refers to Canonical's claims as "a hollow one."
Siego is really not a fan of what Canonical is doing, "what is really disappointing here is that the Free software community is being told a fairy tale in hopes that they will believe it and as a result support Canonical .. under what amounts to false pretenses."
He also calls free software developers, users, and supporters buying into Canonical's Ubuntu Phone claims as being duped. You can read Aaron's Ubuntu Phone comments in full on his Google+ page.
Update: While Aaron disagrees with some aspects of Canonical's Ubuntu Phone plans, he would like to clarify that he is in support though ultimately of this open-source Linux phone.