10XP can provide extra charging capability (e.g, at 2C instead of 1C) than 10S. At 2C charging rate, you could complete the charging in half amount of the time than 1C. But the packs have to be rated at 2C or more. Considering the trend with which the new packs can take be charged, it is a good idea to go with 10XP.

I would also recommend build some redundancy into your equipment: two chargers, two power supplies, etc. to minimize down-time.