The 899 has 2 card slots, I believe the 7 has one. The 899 can be networked to another ff or other hb things like ilink. The 7 is a stand alone unit. Prices on 899 should be dropping as it is being phased out.
I'd go the 899 because of linking capability for me. If I was going helix, then I'd go up a model to a linkable unit.
Edited by Bobby Milam (01/22/16 09:28 PM)