Firstly it was an extremely tragic event, and my condolences go out to their family and friends.
But Paddy is absolutely correct, lightning will take the path of least resistance no matter it's shape or size.
What some people are talking about here are attachment points - lighting is most likely to attach to protruding points and use these as an easy path to earth. You can reduce the risk by designing out attachment points i.e. making them less pointy and protruding.
My advice would be other than get the flip out of there is crouch down into a ball and keep your legs together i.e. making yourself less pointy and protruding!
I was pondering with the same questions over 3 years ago! Then I was using memory map and a Garmin 12 GPS. I wanted a mapping GPS unit and did a comparison between satmap, Garmin and memory map. In the end I went for the satmap due to ease of use, display size and for not having a touch screen. In addition satmap provides a full service and repair scheme which the others don't.
Very happy with my choice it uses OS maps for the UK but you can also buy Harvey maps if you are that way inclined. Lastly the mapping price has reduced for OS maps and are now very reasonable.
I still use memory map to plot routes and review tracks, satmap saves files as gpx which you can import into memory map.
TBH Pen y Fan is my least climbed mountain in the area, much prefer the Eastern Beacons (anything past Fan y Big), Black Mountains (Craig Cerrig Calch, Pen Allt Mawr etc), Forest Fawr and of course Fan Brycheiniog!
I always try to persuade people to explore other areas, Pen y Fan may be the biggest but is so far from the best!