I have no experience with the Holo DACs, but they seem to have a good reputation. They have numerous customer testimonials on their website, including some related to repairs -
https://www.kitsunehifi.com/customer-comments/
I own a MHDT Labs Orchid R2R DAC. I bought mine second hand and when I received it, could not get USB to work. I contacted them and let them know I was not the original owner and wanted to get it repaired. Jiun (the designer) contacted me directly and diagnosed the issue and sent me a new board free of charge even though I had no warranty, not being the original owner. Some of the best customer service I've ever received. If service is one of your major concerns, they would be worth checking out. You'll find a ton of favorable reviews.