Adrian ended up being our tour guide for another tour offered on Viator. Our original tour guide was unavailable, but he set us up with Adrian, and boy were we lucky. We visited the salt mine, the La Certa winery, and a cool monastery on an island in Snagov, which was a nice way to end the day. In all, we had an awesome time.
Adrian was the poster-child guide. Fun, excellent English, and the perfect amount of chatty while not being overbearing. Not to mention his punctuality, respect, and overall attention to detail (water bottles in the car, extra tidbits of knowledge, hilarious stories..) It's rare to get a tour guide like this. Great experience in Romania!