The speed of response when you need it is amazing, I would say that sometimes there can be lag time while waiting to get an answer back but this does not happen often or too much so overall great product! Nothing really at all as yet - just using in development stage with few customers currently (not enough data). Would love to see more integrations into other services we use such as salesforce etc if possible in future versions/additional APIs. We are solving issues around customer geolocation via mobile devices which allows us better targeting of products / content where needed most by our users whilst they travel.