JH was the first place I found out about toku. And most of the old-timers and people on HJU spilled over from JH. I remember meeting most of the people on that board first. And JC's right, it just has a crap-ton of information, links, and presence in the Toku-and Non-Toku community. It'd be a shame and a waste to anyone who contributed to forming and building up the site, not just the forums.
A merger would be interesting; the forums at HJU may be more active, but the database and cataloguing is something that isn't as established as it is at JH. The activity and buzz of HJU's forums combined with the information and data access of JH would be the ultimate.