We've used them for a couple of projects now and so far we've been pleased with their service. They helped us get the backend (database) setup, built our basic UI, provided initial guidance on how to go about integrating it with other parts of our business, and went above and beyond to help us figure out what we should/could do ourselves. I think they're particularly great because they do require a bit of customization (UI layout, integrations, etc), but they're super responsive when we run into problems. It took a bit of time getting used to the way they work, but once we got it figured out, it was smooth sailing. We haven't had any issues with performance, availability, etc. and would recommend them.