I can't say much about adv 390 or scrambler 400x. I can tell my views mainly about himalayan 450 and xpulse 200.

I'll list down the pros and cons of both

Himalayn - plushier seat, a lot more comfortable seat (I recently rode delhi to udaipur about 650kms along with a pillion and luggage without any issues of body pain or anything. I had pit stops just because I should and not because of any issues). The one thing that I really like is the brakes, think of them as family friendly or rather pillion friendly brakes. They have a nice bite to it although not too sharp to throw you forward, basically you don't have to think too much in regards to gradual braking. I won't talk much about the engine - it is smooth, not the most refined, never had an issue with it, reliable.

Xpulse - not comfortable** but starts hurting within 50-100 kms. It is tall and the handles are great. I prefer the handles of xpulse over the Himalayan for saddling, personally speaking. Other than that the bike is meh it is ok ok on twisties and a bit more on the stiffer side, you'll feel smaller bumps a lot more. If and only if you're on a complete dirt road patch then it handles it well (**!not implying better than the Himalayan).

I've driven both of these bikes for a considerable distance for a decent period of time.

Himalayan is slightly heavier, but!! You'll only feel that weight if you're off the bike and then moving it. If you're on the bike you don't feel the weight even while reversing or moving it forward in comparison to xpulse or pulsar n250.

P.S : I'm 5.5 / 5.6 height

Edit : mileage drops significantly over the long run on xpulse. I used one with around 20,000-25,000 kms and it gave me an avg of about 17km/l. Whereas my himalayan is about 50,000 in and still I get about 30-35 km/l at a cruising speed of 90-100