I’ve been using sennheiser for 15 years and never looked back. I currently have the HD595 and I could wear them all day and night (open Back) with no ear fatigue. The bass response is incredible on them, I have tried the 600 series and wow!!! is all i can say. I bet you could find a great set used if shop on ebay or wherever you can find used equipment via trade papers/internet etc. I bought newest set used off ebay for ~$200 USD about 4 years ago. The set I had prior last at least 6 years.
I have other closed backed but I can’t mix with those 
Kenny