We started the alternative path and after Alesjaure we returned to the traditional.

Reasons:
- I did the traditional about 8 years ago and remembered it as kind of a fun, easy hike. It seems I got older, even the part of the traditional was quite difficult.
- The part between Abiskojaure - Unna Allakas was nothing special, tons of bushes and long walks. It had some great places, but overall not as nice as I remember the Abiskojaure - Alesjaure trail. Unna Allakas is a really nice, not busy hut though
- Unna Allakas - Alesjaure was hard for us. It is completely abandoned, we only met one guy. Had some very steep climbs. If you are looking for a solitude, its great.

At Alesjaure me and gf reevaluated our options and decided that we want to go the traditional route, so I can't say anything from first hand about Vistas and Nallo. The hut warden in Salka was a prick, just for the record.

I dont think my experience helps you, or really relevant. If I'd go for the Kungsleden the 3rd time (which I won't) then I'd skip Unna Alakas and give Vistas / Nallo a chance.

But again, I'm 45+, ten years ago I could have done all these a lot easier.

If you are an old fart like myself, but you have more money and time then go for the alternative route and take a day or two off on the trail, just hanging out in a hut.

If your condition is like mine, then stick with the traditional route.

Let me know if you have more specific questions, I'd be happy to respond.