I saw a review of the Janus stuff, what the article said, is that the Janus is for people who are new to motorcycling, and that you soon would be outgrowing the bike if you decided to stay with motorcycling. Yes, they look 'retro,' part of the appeal, but I'd rather have a Honda, just because of parts and re-sale. They have a cool schtick ('handbuilt, you customize it!'), but I think someone who wanted to ride a motorcycle and stay with it would be happier with a 450-500cc Japanese twin instead of one of these. Also, a used 450-500cc Japanese twin will be much-cheaper to purchase. My local CL for bikes has any number of decent bikes for <$4K.
You want 'retro,' buy a decently-maintained BMW Airhead. They last a long time, they have good parts availability, it's simple to work-on with the cyl heads 'in the breeze' for valve adjustments, it's capable of keeping-up with interstate traffic, something I would not do on a Janus! Not in so. Florida, anyway.
I don't know about the rest of the country, but here in so FL you can even find decent Harley-Davidsons for < the $7.500 Janus is asking for the base model, before "you customize it!" The EVO's are usually below that price, and let's face it, even if you're not a H-D guy which of those do you think will be worth something in 10 years? By Gosh(en) I reckon it's the Milwaukee marvel and not the Indiana tiddler.
This year I was in the supermarket parking lot, I saw one of these looking well-used, parked, and when I went inside, I picked-out the guy, he was the only one in the store with a Isle of Man t-shirt on. He said he bought it used for $3K, and he'd put about 10K miles on it so-far, with normal maintenance costs: tires, oil changes, a pair of brake pads. He said, "it always starts, I'm not afraid to get on the interstate with it, and it's a good size."
Can you guess why I like the next H-D? A 2005 with < 16K miles, and < $8K, so it's in the new bike Janus ballpark. This probably has some collectible interest as it's one of the specials H-D makes, a firefighter's edition, and it's loaded with options in finish. Granted, if you're looking for an urban bike, something you can squeeze into city parking spaces, this may-not be the ticket. However, which would you want to take on a 2,000 mile round-trip? Two-up? I have doubts that the Janus could even successfully-complete such a trip. Again, what do you think this would be worth in another ten years, compared to the Janus?
Finally, here is a rare bird, a 2002 H-D Softail with a claimed 1,500 miles! Assuming this is a true figure, you are buying a new H-D for the price of a Janus with some accessories. $8,700, no fees, just tax. Which would you rather ride? Which is (again) worth something in ten years? Which is capable of interstate highway use, and doing it two-up?
I think I've made my point. Anyone who would buy a Janus instead of one of these, is a skinny-jeans hipster, wears his hair in a bun, eats avocado toast, and really isn't interested in bikes.
The Royal Enfield single, before the updated models, was the Real Thing. I suspect it may have been the longest production model in motorcycling. The Honda 50, in both the 'step-through' and the C110 'true motorcycle styling' may-be the #1 largest seller in the world. I believe they've built more Honda 50's than there are people in Germany.