I love doing HIIT, although it's very hard. Especially on the hills - lesser stress on the joints. Plus, by meny studies, besides increasing VO2 max, running hills increases running economy.
About using HIIT as a part of taper could be discussed. In my opinion in much, much lover volume than doing HIIT in any other time of preparation
RE: More Reasons To Love HIIT With The @runningproject