i'm using octane for about a week. realy awesome renderer! with my gtx 570 its really a finecost!
but i have also some suggestions mostly about the workflow:
1) there is no undo. and sometimes it's realy helpful

2) delete and save node are to close together (with no undo function, again would be helpful)
3) multiple import export material nodes
4) linked materials. so it can update in all sessions you've linked the specific node.
5) direct material import from other sessions
6) selecting multiple nodes and converting them to a macro material
7) remember last file location is not always working.
i think some of this would increase the workflow and make it a more flexible rendering system.
again, great renderer!
cheers!