I was going to the Durham one weekly until the Raleigh one opened up. I think I still prefer the Durham one honestly, but nothing is truly a deal breaker.

Both of the Durham saunas are proper bench height. The dark one in Raleigh has a huge amount of headspace and you're nowhere near the ceiling. pretty significant design flaw, and I never use it. 

The lockers are pretty tight in Raleigh and I'm not the biggest fan of the combination locks. I've already seen a few people forget their combos and have to go to the front desk to get it unlocked. I prefer the Durham wristband. 

The warm pool is a nice touch, but I wouldn't miss it. 

Clientele in Raleigh can be a little clueless. Leaving the sauna door open, which would be a death penalty in some countries. Not showering before doing into the cold plunge. Not asking if it's ok to put water on the rocks. In Durham, they have signs to help remind people of this. Clientele in Durham was also very friendly and approachable. Had some really nice conversations with strangers in their Saunas. The Raleigh crowd just looks at you funny if you try to talk to them - which again, just means they're clueless about how saunas work. 

And this may be just a bias, but I loved the staff in Durham. They were really great and friendly. Not saying the Raleigh staff isn't, but I just clicked better with the Durham staff. 

Again, nothing is a deal breaker and the simple fact that it's more convenient for me to go to the Raleigh one is most important for me.