IN my estimation the cube won't cut the mustard unless it comes in at a much better price point across the board instead the one time entry price...
The Harmony hubs come up pretty often in package deals and on sale for really cheap, and the Dot's also come up cheap all the time... The Hub also has the IR Blaster and does a good job even without it unless the components need to be hidden for some reason.
With the Dot+Echo combo, it can be purchased piece meal as well, making it easier to put in your budget in smaller prices. This alone will probably make a big enough difference to most. The Microphone array is too central and a Dot or other Echo product will mostly have better array layouts due to design being for "Any Area" opposed to "by the TV"...
Just one mans opinion on the subject. Thought maybe someone would do such a comparison before now...
The biggest flaw in all of our entertainment systems interfaces is that they have no knowledge of component status. Until someone can come up with a REALLY good inexpensive version of a system that can do such, we will all be grasping for the next great "smart" control piece that works by voice. Or until all of the manufacturers can usher in truly Smart components that have simple protocol Status sharing.