The core team has been great to work alongside throughout every stage our client engagement process as well! We are currently working together for an ongoing project using CQRS/event sourcing architecture which works perfectly within their ecosystem - so no issues here at all yet :) I know it's early days but have seen nothing we dislike thus far from my brief interactions around some initial projects they had done previously (not this one). Our experience over 2 years now was largely building mobile apps used by tens or hundreds thousand users daily across multiple platforms like iOS & Android etc.. Core is very good with their customer service. They follow through with what they say they will do. If there is a problem, they fix it. I have no complaints. If you are looking for a company to develop and maintain apps that are easy to use and look great, Core is the company to go with! We are developing apps for our clients in order to make their business run more efficiently. The apps are very easy to use and the customer service is great.