In any case the UBN Five seems to be at least 1-2 KG heavier than the Vado SL. as Stefan said, the Vado SL has a proven engine and it is nice to have a bike where you do not have to reach out to a different vendor when there are questions / updates about/ for your engine. I have a Vado SL 4.0 EQ and am very happy with it. I use it a lot for commuting in and outside of the city and until recently also for physical training. Rarely needed the booster, battery last long, though smaller than on the UBN. Would have wanted a Vado SL 5 due to the suspension but it was not available at my dealer.
The 7 speed gear shift on the Vado SL is really sufficient and easy to use. The click-fix baggage system is smart too.
Now I got a second e-bike (Scott Addict e-Ride 20) that I use for physical training. Very different from the Vado SL as it is more fragile with the thin racing tyres (got 2 flat tyres already), only weights 11,8 kg, has and abundance of gears and you most of the time ride in the exciting 28-31 km/h speed range where the rear engine does not engage at all. (The Vado SL usually rides at 25-28 km/h, due to its weight , tyres and upward position it is harder to get away from the 25 km/h engine support limit in Europe but it still rides like a normal weight bike). The Scott uses the Mahle X20 engine and the app is faulty, you sometmes get error messages and you need to deal with Mahle directly instead of going to the vendor - unlike Specialized (though ultimately their vendor is also produced by Mahle).
I can really recommend the Vado SL - I love it and it gives you this edge of extra fitness. (The e-racing bike is the icing of the cake for me - both bikes have it's strength)