how long does the bud sit in the iso? ive been using butane and want to use a better way.
Generally BHO is preferred over ISO (I personally prefer ISO because of the ease of the method itself and because BHO isn't very easy to come by where I live, at least not proper quality BHO) because it 'unties' a lot less material than ISO does..
This is due to the polarity difference between the solvents, BHO is relatively non-polar whereas ISO is polar.
Speaking exclusively in purity terms, BHO might be the best choice (in fact hexane would be the best choice but we are focusing on the two most commonly used solvents) but a proper ISO wash & extract can rival a BHO one imo.
So I wouldn't say that ISO is a better way, unless you by better meant an
easier way.
Both methods require a certain amount of knowledge though and have safety aspects that must be respected but I would argue ISO is a bit quicker and also a bit cheaper (although if you have no idea what you are doing you could end up with a vastly inferior end product).
I would not let the Cannabis/leaves/hash, whatever you are using, soak for more than 1 minute, in fact I would say try to keep it to 30 sec max if you want a really high quality product (although I have seen 1 minute soaks produce a really high quality product as well, everything is relative (what kind of quality product are you using in the first place etc.)).
TL;DR - If you keep it ~30 sec you will end up with a clear & pure end product. Strain quickly and remember to cure the oil afterwards.