The other bags that I/my dad have are the NRS compact 70' rope and the h2o Rescue Gear Big Shot and Sidearm. I really like the Weasel because of the extra material at the top, making it really easy to get a good grip on it and throw it, and could see it being easier to use when trying to throw from a less stable area (although standing on an unstable area isn't a good idea). I remember standing on a rock in the middle of a class II+ rapid (Big Rocks on the Noli) trying to throw a 75' spectra NRS rope, and could barely get it to go anywhere, but feel like I could easily make the throw with this rope, because of the ease of throwing. If the bag was a bit more tapered towards the end (longer and narrower like the Sidearm), and the available belt was better designed (I like my Sidearm because you buckle the belt on, with the rope clipped on via a QR buckle). The rope itself feels like it's almost hollow on the inside, but it's rated to about 1888 lbs of force, which is stronger than my 5/16" Grabline in the Sidearm. I'm somewhat skeptical about their strength claims considering how it doesn't feel like it has a core, but for just swimmers it should be fine. I could see the handle on the bottom of the bag being a snagging hazard as well, and may cut down the rubber sheath on it, similar to how the h2o bags are (not enough room to get a hand in, but enough for a carabiner).
Will this be my primary rope? Probably not, due to the ease of access of my Sidearm. Will I still carry it with me? Definitely. The ease of use is great for someone who hasn't thrown a rope before, and the added length to the Sidearm would also be a benefit on some of the wider rivers in NC, like the French Broad in particular. If hf begins to export to the US, I'd definitely look at getting the waist belt attachment, but from what I've seen online, it doesn't look nearly as quick to access and robust as the h2o (the straps holding the bag on to the Swifty belt seem like they wouldn't deal well with pressure).
Overall, it's a great rope, and if their products were more readily available in the states, I could see them emerging as a serious competitor in the industry.