Always happy to help.
I've never owned REL or JL Audio (they're a little out of my price range), so I've never had the chance to listen to either long term. I've only heard REL in dealership systems. Though I do have a rather well-to-do friend whose dedicated home theater room's sound system is anchored by JL subs, and they are most impressive.
However, SVS make subs meant to be heard, not seen. They may not be lookers, but their performance approaches all but the top tier of JL or REL - at a much lower price point.