I signed up to the ABC Active Memory but got bored with it as I was already at the upper end of their scores, and I found it was hand/eye co-ordination and internet speed that were the barriers. I couldn't click any faster and some activities had a delay with up/down load but the clock kept going, or I clicked where something was, only to have an error as the screen was still re-drawing. Long after I left I was informed that the database had been breached and email & passwords revealed.
I have not tried any other Brain Training on-line, but I am an avid learner and do puzzles (crosswords, cryptics, logic, maths & codes) and jigsaws in my spare time. My ABC experience has put me off doing them (on-line training aps).