Hello Thomas and welcome to Simply Discus.
You will get mixed opinions on R/O unit brands. First of all what is the purpose for...etc. for breeding discus?
As for booster pumps...this is only required if you have poor water pressure from tap source...etc. water pressure below 60 will require a booster pump.
Are you on well water? or Municipal water?
I don't have any first hand experience with this model but looking at the customer review it does appear to be good.
Budget and volume of water per-day needed is what you will have to research or you may get another opinion / recommendation from another poster.
...Ralph