This sounds a lot like my dilemma. Did the Braveheart a few years ago, so that got me a 70.3 up the Ben. Last year was half Brutal, which got me Snowdon. This year did the full Brutal. Because of high wind the start was delayed, and the swim slightly shortened. They also shortened the run slightly but not by a huge amount. And 2020 entry is already in for Triathlon X so if all goes to plan will have done 3 Peaks.
The Braveheart bike was simple, out and back, but the run was hard. The Brutal bike course was harder but the run was easier. The laps around Padarn are deceptively hilly. Great fun coming down Snowdon this year at about midnight. It is a really clearly marked path and I could run the whole way down. I am not a competitor, I just do these for the personal challenge. I finished this year in 15.44 off maybe an average of 7 or 8 hours training a week. If you fancy something unusual give the Brutal a go. It is really friendly, and because they run a double, and this year a triple they can be flexible about cut offs.