I do not own one, nor looked through one.
I did have a long conversation with someone who has had one for several weeks now.

By all accounts its a very accomplished piece of kit with a compatible scope. Its an add on so has all the pros and cons these come with. Best with a scope whose side parallax is down to 30m, which is better than 10m/15m that some add ons demand. Its a handy spotter, and well made.
At the right price this would do, as is, for all rat and rabbit, so fine for .17HMR. For fox then it would need a good IR torch to boost the range to a tad over 200m practical. The picture it gives is sharp and clear. Loads to like about it.
If you already have a WFV700 or 800 then its not going to better them on pure absolute range. If you don't need all the range then its the one to get.
The DSA may not fit every scope but then the WDV's had the odd problem too. I think this unit is a tad longer than the WDV when fitted, but still usable without drastic changes.

For many this unit will be ideal.

Over the next few weeks I would expect a good few reviews, and with built in video then some good footage. I would like to see some pictures of how shooters fit behind it, and the rifle set up done.
All very promising.