I’ve got the Microfreak, but I have only some information of the Easel from internet sources and after receiving a virtual Easel with the Arturia V collection I spent some time to explore it, without the keyboard though.
Concerning the sound I wouldn’t compare the two. The Easel creates sound by wavefolding and by FM with Buchla circuits. The algorithms of the Microfreak provide both to, but AFAIK they can’t be used at the same time and sound a bit different. IMO the Microfreak offers quite different sound creation options with all it’s different algorithms, if compared to the Easel.
Concerning the operation I would say that the Easel shines with sliders and it’s semi-modular hands-on concept. This allows to go very different ways for sound creation and performances.
IMO there is some similarity, indeed, but both concepts are very different too and create totally different beasts.
I hope this made some sense … 