I made the switch a little over a year ago and haven’t looked back. I still have CS 5.5 on my machine that I can open most newer documents, although it does come up with a warning, so as long as you’re not dealing with complex gradients or similar complexities, it is fine. Just as an FYI, I also use Coreldraw occasionally and it is fine, but I prefer the Affinity products.
Yes and no... The suite of products that Affinity offers can replace adobe’s products, but there is not yet translators for opening ID files. Most of the other files (.ai .psd, etc) can be opened and worked on, but there are some limitations as one would expect to experience trying to decode other software developers formats. That being said, if you’re not trying to share files with adobe users, you can easily move your workflow to Affinity and be just as productive and not be tied to a subscription model for the rest of your design career.