Really they are different products. It depends on your situation as to what you have and what you want from these products. SSR2.5 is a fairly aggressive abrasive cleaner that works well with a PC but if you try to use it by hand it will cause some marring IMO. SSR1 is a mild abrasive cleaner and polish and may be used by hand or machine. Both SSRs contain no wax or silicone and are both great for polishing out scratches and defects.
AIO is a one step product that cleans and provides some sealant protection. It is different from the above polishes.
It depends on what you need the product for as to what you are buying here. They are all very good products.
