It's a great product, well worth the money. I used it before with Modo and it worked well even when you had to re-export your HDR every time. Modo would see it had changed and I would tell it to reload and not bother asking in future then it pretty much automatically updated in the render view as I played with the lighting. The new methods to load your 3d scene into HDRLS speeds it up even more.
If it feels expensive, just remember its not only a Modo plug-in, it works with a lot of 3d apps and as somebody who jumps between Modo, Cinema and Maxwell it feels well worth it to me.