I'm with stu on this one. I used a casio digital watch that I bought from amazon for about £6 a couple of years ago. It doesn't show pace or tell you what distance you've covered but if you're starting out and just want to know how long you've run for, and to record some splits over a measured distance outside, it's ideal.
The garmin I later bought was basically just a toy to treat myself.
If you're planning on adapting some of the long runs in the P&D plans to have more 20+ milers than they prescribe, how do you plan to do this? Peak at 20 earlier? Make some of the 17/18 milers into 20? Presumbly you'd still want fallback weeks to help recovery, and MP weeks to help tune the race pace, and want to avoid back to back weeks of 20+ mile runs?
Wondered how the plan might look if extending the number of 20's.