My five nastiest juices, in increasing levels of disgust:
5th worst. Orange Dreamcicle from Ms. T's. Trust me, you'll never get this out of your atty. Good reason to switch to the relatively disposable cartos. I am saving this in case I ever run out of Ipecac syrup. This would make a fine emetic.
4th worst. Johnson Creek... The only one in the sampler I kinda liked was the Mint Chocolate. This was the first juice that I had bought, based on rave reviews. It almost put me off of vaping. Fortunately, for me, the carts that came with my Blu & Volcano convinced me that there was hope. I still keep a large bottle of Tennesee Turd around. It works well for cleaning the sharpie writing off of my cartos when I wash them out. Oh and very nice bottles!
3rd worst. RY4 from Alien Visions... I see they dont sell that any more. Excellent vapor, but a certain putrescense (sp?) that I just couldn't get past. Maybe buffalo ...? Something on four legs, that chews its cud. I actually like(d) the RY4 from madvapes (dekang I think), but just got more from them and it appears that the formula changes wildly.
2nd worst: Blueberry Cheesecake by Tasty Vapor. Highly rated and loved by many. Didn't work for me, although my gag reflex did get a pretty good workout. Fortunately I had ordered several juices from them at the time. The other 3 worked out well and they remain my favorite vendor. I have about 16 of their flavors and 4 of my TOP 5 favorites are TV.
Absolute worst: Wintergreen from Madvapes (top vapor). It started off OK. First couple of hits seemed OK. Kind of a nasty aftertaste... and then... a growing level of disgust, followed by overwhelming nausea washed over me. Next thing I knew I was praying to the porcelain god. One long, protracted technicolor yawn. Talk about barfelofous-of-the-blow-hole! Tossed up some perfectly good Applebees that night... and came darn close to soiling myself. Anyway, put me off of mint flavors (and chicken alfredo) for a full week. Nope, Ralphy doesn't like the Wintergreen.
NOTE: With the exception of JC & AV, I have gotten some fine juice from the other 3 vendors. This is just MY experience.
ETA: I would recommend ordering at least 4 diverse juices from a vendor before deciding you don't like the vendors juices. Chances are, if you order 4 you will have two vapable juices, one that you really like.