WLP500 Trappist Ale is supposedly similar to WY1214 Belgain Ale, which is the Chimay strain. (
Source)
However, I've heard that Chris White obtained the Chimay strain
before Chimay switched over to cylindroconical fermenters, while Wyeast obtained it after the switch. When Chimay made the switch, they scoped their yeast and selected for optimal performance in conical fermenters, rather than focusing entirely on flavor/authenticity. I don't have a link to support this info; it's from a brew club member who I'd describe as a "walking beer encyclopedia." This meaning that WLP500 is more authentic to the older pre-conical fermented abbey ales of Chimay, and the WY1214 reflects the newer strain selected for conical fermentation performance. I won't guarantee this information, but I did hear this from a reliable beer geek/brewer. Can anyone confirm this?
Regardless, I've done side by side comparisons of the same wort in two different fermenters with the WLP500 and WY1214. I have to say that ultimately the WLP500 is better IMO. The WY version takes on that abbey aroma and flavor sooner, but doesn't age as well. The WL version initiates with a somewhat bubblegum ester that diminishes with some age, and ends up as the best tasting (and closest representation to classic Chimay flavor) homemade Trappist style abbey ale I've had.