I just realised that those prices are without the Heart rate monitor strap - I'm sure if u look around online you'll be able to get with the HRM strap - maybe Wiggle - if not just look at shopping results in google. Runner's Need tend to overprice everything...
I find having the GPS on my wrist, rather than in my pocket on my phone really helps, as I can just look at it quickly to see if I'm keeping pace constant - you can set up this thing called training partner, and what pace you're planning to go at, and it will alert you when you're going too fast or too slow. Of course you have to run at a pace thats comfortable, but I find I set it up for slow and try to stay slower for the easy runs, and then for the faster ones, i set it up faster, and don't beat myself up if I stay on the fast side. Though I still try to keep it even. I was going for a 9:20 marathon pace for my run on Saturday and ended up at around 8:55, which is fine by me, as I managed even splits throughout the run, but before I had the garmin, I probably would have done the first mile at 7:30 and then burned out for the rest of the run ending with the last mile at 9:00. So in summary, YES, it is definitly helping me in pacing.
DS2 I downloaded the P&D book and read the first chapter... Its convincing me that one day I might have a chance of qualifying for Boston