When atom first came out and i tried I said no thank you as it genuinely was painfully slow.
I have been using atom now full time for 3 weeks and gave it another chance as I love a lot of the plugins it has and the community and I am very impressed.
Regarding its slowness it has improved a lot. The only complaint I have with its speed compared to a native app like sublime is that it is slow in starting. This doesn't affect me much as when I am working on a project I leave it open all the time anyway :-)
Give it a try and get some of the useful plugins and you will never look back.
Start-up and creating a new window can still take a good 3 seconds on my machine. Visual Studio (the huge IDE, not VS Code) is actually faster to start most of the time.