Thanks for the feedback Mark, I agree that the iS150 is probably going to be a better bet for my needs.
As a side do you think I could get away with a North 9.8m F10 RAM (which I have just ordered) on the 144? it's just a thought. I may consider keeping the FF158 given the great service and enjoyment it has given me.
PS - I have just seen a new thread on big kit which adds interest to the discussion.