I have several brews in on these and they work like a charm. There will be some condendsation on teh outside of the bag (in the bucket) but a quick rinse and all is good.
Filling the bag is still a little tricky and I have yet to find the best way to do it other than just do it. You have to manage the air release from the outside of the bag.
It's also kinda interesting too when you have pulled the bag, tied a knot in it and have set it aside, waiting to go into the trash, to have it inflate. Thankfully, the only one that has burst was in the trash. I have since been dumping the yeast into the compost.
I have yet to find any bags larger thanm the 18-24 pound but, they work with just a little cautionary effort at filling.