I had a core and had to send it back twice. The second time I asked them to send me a 2nd gen Kickr and they did, been happy with it ever since.
The cores are good-ish, especially if you get one without issues. If yours has an issue you will know before your 1 year warranty is up. Wahoo’s CS is very good. I would not recommend cores or 2018 Kickrs to a friend though as it’s 50/50 on if you will have a problem with them.