Hi Mick,
I have used both for a number of years now but normally I wouldn't bother with the Mono Pod unless I was using over 200mm fl and looking at almost a snap shooting scenario for wild life or sports event.
You mentioned 28-70mm was your maximum and landscapes as desirable, my personal choice would be the tripod if you were expecting a lot of low light situations like sunrises and sets etc, but if you anticipate reasonable lighting conditions then the mono would achieve both outcomes quite well and be a lot less bulk and weight to carry. hope this helps.
Cheers