You might be hearing the internal Leslie, which tends to be more extreme than guitar modulation effects. Also, the vibrato width might be adjustable on the H100, not sure.
As far as value, it's priceless Unfotunately, not a sought after model, and difficult to give away for free. Extremely heavy, very complicated, not as reliable as other tonewheel consoles. Not a lot of organists left these days, but literally millions of organs still out there. I can't suggest a price--it's a buyer's market, and I doubt the seller will find too many more prospective buyers, if any. Personally, if a mint H was offered to me for free, I'd have to think long and hard about taking on a 450lbs organ that is difficult to repair, despite the fact that it is a great sounding instrument.