Of those I'd choose the dragon. That more robust heatblock is way too appealing.
Second choice would be the BiMetal. Easy to install, and Triangle labs do good work from what I've heard.
Contrary to what aardvark says, heatcreep does exist, and is quite common if printing in a hot environment (e.g., enclosure, or a hot room). However, the V6 is usually quite robust against heatcreep. It will need a new mount though (as per the Dragon). That would be my third choice as it's fiddly to work on compared to the dragon