I purchased a WDV800 a few weeks ago, so far very impressed. Definitely better on certain scopes, works very well on my S+B not so good on my NF. No idea on a Swarovski sorry.
Its not not the best looking of things but very well made, seems very robust and is simple to use. Mine came with 3 shims which allows fitting the WDV to all my scopes, that said if I keep it I will get some shims machined up for each individual scope to ensure a good tight fit.
I also purchased a Sunranger / Ruby IR torch with the 800 which works well, I’ve not tried my other IR torches with it but given they are less powerful one assumes they would not give the WDV the same performance.
Shot a few rabbits last week with the WDV fitted to my 22 Hornet around a 100yds or so, no problem. Definitely good around 8-10 mag, less clarity at higher mag but maybe a few tweaks / different scope would sort that.
Tried it on my 243 / 7-08 / 308 all without issue.
ATB
T