I have made a long test of the bike today - went through the Nuuksio National Park (around 20 km in the park, 42 in total).
1) Every hill on the route was conquered - in some cases it was not so easy (even though it was first gear and assist level 3), but it was possible still sitting on the saddle (for example, hill on the photo has angle of 20 degrees to horizon).
2 I was really impressed by tires (Marathon Plus Tour). If at first I drove carefully around the turns then closer to the end of the ride in the park I trusted tires and drove more relaxed and faster. Also driving uphill on the gravel (sometimes not so small, like on the photo) tires had good grip - there was almost no slippage.
3) During the first part of driving in the park when I wasn't sure about tires yet, I've used rear brake a lot - as a result at some point it was overheated a bit - brake disc surfaces got dark color. But shape was kept. So, it looks like a 160 mm brake disc is not enough for riding on the high hills.
4) Battery capacity looks good from my perspective. After 42 km there are left about 25-30%. But according to the driving conditions it looks good:
- First 13 km before I entered the park there were 175 meters of moving up (according to Google Maps).
- In the park there were many hills where first gear and assist level 3 were in use.
- I'm not so lightweight guy (100 kg).
5) Most of the time I used gears 1, 2, 3. Very rarely - 4 and once - 5 (when on the long downhill I decided to check what could be max speed - I've got 52 km/h). So, for me it looks like that it'll be better if gear 5 became gear "0.5" - to move gears range to the lower speed, but higher torque. Potentially (I suppose) rear sprocket can be changed (from 24T to something bigger). Also the chain should be replaced in this case. I'll keep this idea in mind.
As a conclusion - I'm satisfied with the bike (price - value ratio is incredible).
P.S. One minor concern - when riding on the gravel there is one "grig" appeared in the place where the rear fender is in contact with steel wire bracket - no idea how to fix it at the moment, but will try to find some workaround.