We recently purchased the 10m biothane long line to replace a DIY rope one I had made. Kepler (my border terrier cross) and I adore it - soft on your hands (doesn't cause rope burn) easy to clean, and reeeally nice to handle. It also doesn't slip out of your hands like I expected, easy to get a good grip on it when shortening it (my dog is only 12kg so may be harder with a big dog).
Very sturdy so far, perfect for a terrier who enjoys getting as filthy and tangled as possible!
As it's so soft it doesn't get tangled on roots and sticks like rope ones tend to. Very good quality handle and metalware. Amazing way to add lots of freedom but still have control when we get surprised by a rogue rabbit!!
I highly recommend it. Yes it comes with a cost but well worth it for how sturdy and good quality it is. Also as a plus the packaging was really cute ❤️!!