Talk:Gate to the Aperture - Purified Soulstones/@comment-1469209-20150515191508

This new soulstone battle in the black hole may not be as great as it appears. If you had 21 keys, for example, you could do one of these 3 times for a total of 606,000 exp. However, with 21 keys, you could do path of soulstones 7 times for a total of 714,000 exp.

This means that the older stage gives you more exp per key. This isn't to say that this stage is bad to run in every situation. If you are running it just for the prime soulstone for use with a madhead, then it's totally worth the extra key.