I enjoy this app. Ive tried many brain training apps, and this is my favorite all around. Lumosity is cool, but Id rather drink bleach than pay for their astronomically high prices. The games on here are more numerous and versatile than theirs (never played Lumosity online games, but Im only speaking of phone versions). The interface is user-friendly, but a bit slow paced. Im never patient enough to read the instructions to the games so I skip through them. However, I am glad they are there because I hate it when Im stuck with an app I dont know how to play. Fit Brains interface is nicer and quicker in my opinion, but after their moderate-length trial, they still want $50 for their (forget if it is year or lifetime) membership. This is still WAY cheaper than Lumositys robbery. Im glad they have enough games where youre not bored with them in 3 days, and theres not too many where you feel youll never have the time to gain some level of mastery over all of them. Ive seen improvement in my speed and capacity over the past 2-ish weeks Ive had this app (and I do play everyday). The reason I give 4 instead of 5 starts is 1) for the slightly slow interface and... 2) their results/scores pages arent very useful. I wish they would make it so that you can compare scores for each game and exercise chart so you can see how much you improve in each area rather than having these barely perceptible charts and meaningless arbitrary values for game scores. One last thing... I like the encouragement from Einstein; its a booster. So in my overall opinion, its worth every penny.