Forgot to respond to this - I've done all 3 plans, at any one given time! I used Higdon's absolute beginner plan, but then modified his beginner half plan with a Galloway twist - I did all the mileage / training days Higdon suggested, but I used a Galloway walk interval - one minute at the end of every mile. I'm currently doing the Train Like A Mother Own It 10K plan for the Peachtree on July 4th.
The main diff. to me in Higdon / Galloway plans is the mileage for the long runs. Higdon has you continually adding miles while Galloway has you add, then take a step back down every 2 weeks before you add again. I think if you are injury prone, Galloway might be the "gentler" plan. I followed the Higdon plan to my first princess, but the summer after that I got shin splints. I think it was more due to the way I was running and not how much I was running, but it's a consideration.
I really like Train Like A Mother b/c it has a variety of work outs. I needed something to shake up my routine and focus on strength and speed workouts, so this fits. I'm enjoying it. I"m not following it to the letter (as in, haven't run once this week b/c I've been busy with the kids) but I do like the variety. I'll definitely be using their half plan for my fall half marathon - once the kids are back in school and I have more of a set schedule.