Ordered a WattBike Atom Next Gen this morning. Sadly 11-15 weeks delivery window so it will be a while before I can compare it to my Kickr 18 wheeloff. The smaller footprint than the bike plus the Kickr was the main reason and an ‘easier’ adjustment between riders. Also with the price of used bikes in the UK being so high at the moment I can offset a bit of the purchase price by selling my dedicated trainer bike 
I hope the TrainerRoad team can get the geared mode working with the App at some point but I mostly ride in ERG anyway