Again, from my side. If you are a professional and need to work out a lot of ideas in a quick manner, the shape builder tool is essential. It's the one tool, I - and MANY of my friends can't miss and that's why I cannot recommend this as an 100% alternative to illustrator.
Sure, technicially spoken it does kind of the same thing as the boolean tools, but if you have plenty of shapes to combine, you may have to do a lot of work to make it happen. For me personally, I've purchased all products by Affinity, but can'T use them to my speed.
With version 1.8 I'm very happy with a lot of newly added features, but I hope for 1.9, the shape builder will be added. People desperately search for alternatives to the Adobe cosmos, but I believe, it still takes quite a bit of time.