I have a V12 and had V6 cordless before and I am quite impressed by these including the Pencil one. It made vacuuming at our home quite simple even for kids. Where do you see they are lacking?
Okay maybe I am an outlier, but when I vacuum my place (1400 sqft), it takes about 1hr. I fill half of the container with dust. I am kinda thorough, maybe borderline OCD :)
And so I need a vacuum that is not going to lose power, so I am happy to stay corded, with full sucking power all the way.
I can see the Pencil useful for a quick limited vacuuming.