I thought SuiteDash could be the one to bring them all together under one roof.. but it isn't quite there yet.

The UI feels slow, if you ever used phpmyadmin, the responsiveness feels very similar, it's just that SuiteDash has a spinning circle animation between pages (which you see often).

As for the UI/UX choices, stuff isn't where you would expect it to be, and many logical flows are structured differently to what you'd expect. It's just an interface that demands learning from scratch and get used to. And the fact that it isn't very responsive doesn't make it a particularly enjoyable learning process either.

Invoices: I use Wave Accounting - it's free, and they produce beautiful invoices, receipts, reports, email notifications, and it's incredibly simple to use and to customize. Even if you never used Wave before, you will learn the interface almost immediately, because stuff happens to be right where you need it to be.
In SuiteDash I found myself having to often close the page I am on (not just with invoices), to try and think where could some option be, realize it's in a completely different part of the website, leave the page I was on and lose the progress, change this one setting, then try and find again the page I started from, to start over.
If the whole point of having an all-in-one solution is convenience, then maybe SuiteDash isn't the right tool for the job. I find it much more convenient to switch between 4-5 separate tools (which I learned within minutes) than I find navigating around SuiteDash.

For documents, I use both DocuSign and PandaDocs. SuiteDash is easy to use when it comes to documents, although it has its own ways of going about it, which again, you need to learn about. I would probably choose SuiteDash over the alternatives; it isn't the best of the 3, but the LTD and how easy it is to write and style OK-looking documents makes it a good choice. However, the signature font is hideous.

Who does it better:
CRM - HubSpot
Invoicing - Wave Accounting
Project Management - Nifty
Documents - PandaDocs
Calendar - doesn't integrate with anything, good luck using it
Storage - no integrations, but has its own
Messaging - can't chat to customers (why?), only team members - Slack

Knowledge base - I thought this was brilliant, until I realised that I can't assign articles only to certain groups of people ('circles'). I have to use 'Pages' instead, which is defeats the point of having a knowledge base.

Forms, flows, and pages are very clever however. Domain integration 10/10.
White labeling is OK, but needs a lot of custom CSS to get it right, and you can't choose fonts. Again, getting this to match your business entirely takes so long it's probably not worth it.

I doubt that I will be switching most of my operations over to SuiteDash (maybe just the contracts?), but I can see that a lot of work has been put into, so I will give it some more time and maybe I'll end up using more of it and keep it.