The only real similarity is that the Felix has a height adjustable handle (to 3 levels of height) swivel joint and removable PN to make it a shoulder vac if you buy optional shoulder slings or if you want to change over to the parquet hard floor cleaning brush floor head.
Personally I can't abide either design as a hand held vac. If I was going to have a vacuum cleaner with a shoulder strap it would be half the size and not as elongated and bulky.
The Felix was designed by an ex-Vorwerk designer, so its no surprise it shares a similarity to many on sight.
However, now that I own a Vorwerk, it is like night and day versus the Felix; the Vorwerk is light, far easier to push and cleans well as an upright vac. But it is like Kirby though in terms of having to dismantle everything to use smaller cleaning tools or specialised floor heads.
I prefer my Sebo Felix at the end of the day. It is far more capable given its short hose on board and has cleaning tools that I depend on all of the time. It is also far better built than the Vorwerk I own and the dust bags on the Felix take far longer to fill up. Cost effectively the Sebo Felix is also better value, long term. To gain the lightest weight when pushing it, I have changed the roller brush over and put the height setting to number 3 out of the 4 height selections.
This new VK200 is stunning though in terms of its look and what it can do - but it reinforces having to dismantle it all of the time to get the best out of its attachments and that still includes having to take off PN etc to add the long hose and smaller cleaning tools.