You do need some understanding of PHP to use Types on its own, as you will need to insert the new types of data into your existing themes. If you are happy creating a child themes you should be fine.
Types, does become really handy when combined with the developers premium plugins. It becomes possible to create quite complex websites with little/no knowledge of PHP.
I made my design portfolio website using Types and Views, it meant I could tag different parts of each design project as CAD, Prototyping, Photoshop work etc, and let people view either a project as a hole, or just the parts of each project that contain aspects that interest them.
The developers are also extremely active and updating and fixing bugs very fast. I also found there customer service really good. After I paid for Views it was possible to rely on any question being answered in hours not days. I have not used the community forum for help much. But it dose seem to be quite active so that might well be helpful as well.
On the down side - it can be really really hard to understand what is going on with the naming conventions used (with Views more so than Types). So many aspects that seem to be doing similar things but are really hard to get your head round.
For starters though it is clearly stated it is a little confusing that Types creates data fields, then dose nothing with them. Working out how to insert the right information into your website can be mind-bending hard sometimes.
Buying Views as an add on helps... but at first not as much as you would hope. Not because it is not capable, but because of how it describes what it is doing. You have both views and view templates and both do similar but different things and I still (after over a year) have had to look at the documentation each time I have wanted to change something. They are just too closely named for me to remember exactly which one does what.
Partly the problem is that they are doing something that is pretty complicated. They do it well and do make it easier, but you still have to get your head round what information needs to be put where, and where it is going to be got form.
All that said, the support (for paying customers) is really great and the plugin works reliably well. So the problems of getting to grips with it can be overcome.
As a designer, happy to use HTML and CSS, I can imagine Using Types and Views on all web design projects I do in the future. It means I can create easily updatable websites and not spend any more time than is completely needed learning PHP.