Being able to use it as a commutation/portal with my clients in a creative agency type capacity is fantastic. It replaces the need for many tools at one time. Using that way allows for transparency on the client end, too, since they can be notified every time we complete a Pinterest Pin Design for them or an hour of Pinterest VA work, etc.
Having tried many Project Manager tools, Hubstaff Tasks is the most drop-dead simple to get started with a simple workflow quickly. It has the core features you need to get up & running with a Kanban flow. It's easy to make a quick board either with a blank template or one their preset workflows. Very low-friction.
There are a few basic things that could improve the product. Being able to Copy & Paste a whole project (or even just a card) & just re-title it would be great. I use the service as a portal for my Pinterest Pin Design clients (www.pinpals.design), so just being able to reuse the same reject over again for a new client, rather than having to create a whole new project from scratch each time would save me a lot of time each month. Also wish that the site worked a bit better on mobile. I've noticed it's too easy to drag an item out of place on touch interfaces, etc.
It's a simple to use and really fast to get up and running. I use it with Hubstaff so it connects easily to our time tracking setup.
It's still new, so features and improvements pop up on a regular basis but there is room for things to keep improving.