Choice between two different integrated tube amps (SET & PP)

set vs pp is just one dimension of difference of probably 10-11 relevant attributes

That this is true is an understatement.

There are simply too many different variables at play here to even begin to speculate. Unless you wish for general statements about the characteristics of a PP Vs SET - and they are known and have been discussed since time dot.

To which I add my own experience of no relevance - I have a SET and a PP.  The SET has been in storage for a decade because it is ugly.

I would never spend that kind of money on the Willsenton.....  I have listened to several Prima Luna and they sounded pretty good.  I would say support on the PL would be better just because Upscale is the distributor.    

Stay away from Willsenton! It runs the 805 tubes at over 1000 plate volts. Long-term reliability is suspect! All new production 805's are from China. PL EL34's are readily available and affordable from European manufacturers.

Anybody have experience with either?  Have read great reviews of each of them. 

Seriously?
Have we ever seen bad reviews? 😁

I got the PrimaLuna Dialogue Premium HP, used, from a friend who I have gotten other amps from. It seems a bit light on bass, but it was after a change to a new house and room, so I am still working through it. And It’ll probably be better once I get the VandySub hooked up, and the remote is fun to use.

If your example is an integrated, then it seems like it is a different model?

Also I did get some KT120s but have not put them in yet,  so if you get the PL then hold off and you can consider upgrades later. I kind of rushed in, but I might sell it locally, as I have been seriously been considering either Purifi based class-D or Atmasphere.

It was $2k (USD) used and the full tube upgrade was ~1200 AUD (900 USD).

It is definitely good enough, and sounds pretty good. What you are driving them with could help to know. I feel like it is marginal on power and it is rated something like 40W Triode and 80W UL.

There is no dishonour in a demo unit, going slow, or more hand wringing.
I baiscally needed and amp, and this was sitting there, so I got it.

The Willsenton runs 48wpc, so power output may not be issue. I owned PL Dialogue Four, self modded with Takman and MIflex caps, until very recently. I also own 845 and 300B SET amps. High power SET creates lots of heat, heat is enemy of audio components, 48wpc is an awful lot of power for SET vs even the 18-20wpc of 845 tube, so I'd expect even more heat from 805 amp, plus you have active line stage which mean more heat, all on circuit boards within relatively small enclosure. The Willsenton scares me, I like to see point to point, separate line stage or at least passive linestage here. And yep, 1000v is nothing to laugh at, any failures will be catastrophic. If you were intent on SET, I'd prefer Line Magnetic, assuming it has enough wattage for your needs.

The Willsenton could have very nice sound quality, perhaps better than PL, but based on reliability and build quality I'd go with the PL. Any possible issues with PL will also be taken care of by Upscale, very good techs there.