Steve, I'd advise you to continue to hold out and wait for them to make a joint membership for both InvestorsHub and Silicon Investor.
I use both forums about equally and could never really decide which one I would prefer to join.....so I hold out.....waiting for a joint membership.
"Our houses are such unwieldy property that we are often imprisoned rather than housed in them." - Henry David Thoreau, Walden: Economy, 1854