I can't speak for a comparisan, but I used USMLeasy exclusively to study for step 2 after making my way through First Aid once. I did every single question. step 2 of 241, but our end of the year NBME clinical science exam predicted a 250+ (lots of OB/GYN on my CK test, my weakest area, one block was like every-third question OB/GYN - it couldn't have helped my score). USMLeasy was great, especially the way they simulated the test interface. explanations were thorough and the test allowed to you see your percentile against others students using the web site.