I like that it has very clear pricing plans so there's not too many surprises when signing up or trying out different features/apps! It does have some glitches here & then but they are working hard at fixing them as fast as possible which makes me feel more confident about using their product long term (or even switching).
We use unStack mostly because we needed an easy way to build our own custom WordPress site without having technical knowledge - plus all other services were either overpriced / didn't provide enough options etc..