I've read that some of the water bottles are MADE by Better Bottle Corp.
Either way, to answer the OP's question, I use them and all of them have a #1 except for one, it has a #7, which is classified as "other". I notice no difference between the beer made in the 7 from the ones with the 1.
I like them because with the regular cap on top, the hole in the middle is 5/8", so all I do is stick a 5/8" OD vinyl hose in it for a blow-off tube. Simple.
I don't hesitate to use any of them and have for 2 years now. I have no issues with them at all. As far as O2 permeability, I've never heard of anyone who actually had a beer ruined because they used a water bottle and O2 permeability was the DEFINITE (as in proven) culprit. But yet it keeps being repeated as gospel.
I also use 4 buckets (#2) with no problems. And they don't have rubber o-rings on the lids so they don't seal airtight. I've also used a bucket that doesn't have a lid, so I rubber banded a clean towel over the top. Worked fine.
But I admit, I've only been doing this for 2 1/2 years and have made only a little over 300 gallons of beer. I guess if I keep taking chances like this, I'll have a ruined batch one day.