another big plus is the keys on the ASR 88 are weighted and are larger. In other words, they are identical to real piano keys. Compare and ASR10 keys to the 88's keys (if you can) and you will see a world of difference.
From the ASR service manual, they say there is a difference in the software for a ASR10 and 88, but they don't explain it too detailed. From what most people say that have used both, they don't notice any difference in functionality. So, the difference in software is negligible.