I haven't used them myself but they have a good reputation. The only refillable notebooks that I have I have tried were from William Hannah and I had a few issues.
https://williamhannah.com/
First off was the price at over £100 for the bare essentials, you then need to buy a lot of pages to make it work. I also wasn't sure what I would do with the filled pages, should I store them and how. The notebook book itself was also quite small, especially if you are used to A4 paper and also I lost some of the width of the page because of the ring system, my hand was forever bumping against the rings, I had the same issues with Filofax.
My working life was involved with infrastructure projects and I used to keep individual notebooks for each project, these were easy to file when the job was finished and also easy to refer to in the future, especially if you date each page of notes. I had one situation where I needed to produce in Court my notebooks as evidence of instructions. The judge accepted my notebooks as evidence and said that he would not have accepted any computer notes or a loose leaf ring binder as they could have been altered. My notebooks were case bound and dated on each page.
The Rhodia notebooks from The Writing Desk are excellent for the purpose.
The UK's longest established independent fountain pen specialists. Sailor, Pelikan, Edison, Parker, Namiki, Visconti, Faber Castell, J Herbin, Clairefontaine and more[i]ps_[i]1.6.1.18[i]118[i]ps_[i]1.6.1.18[i]118
www.thewritingdesk.co.uk
I hope that others can chip in with their experiences of Atoma.