I'm with Graham, SPD's or egg beaters. SPD's give you the option of a bigger pedal area helping to give confidence when doing flying remounts and trying to clip back in. Not sure how the straps would cope with rolling dismounts and step throughs...
I'm not sure this combination of strap and pedal would work for cyclocross racing, where you are constantly jumping on and off the bike, which is very different from other types of riding. Your feet get very clogged with mud and grass and you have to get your feet back on the pedals very quickly without looking that's why everybody who races use either Shimano SPD mountain bike pedals or Crank Brothers Egg Beaters. I've recently changed to Boardman SPD pedals available from Halfords which are Shimano compatible, cheaper and offer better mud clearance. Even cheaper with your British Cycling membership!
No need to buy special shoes, they secure your feet to the pedal so you can pull up perfectly well, and you can get your feet out in a nanosecond without thinking - no more silly falls because you didn't unclip in time. Don't think they're just like toe straps because they're not. The fact that they go diagonally across the pedal makes all the difference.
However peer pressure and marketing pressure mean you won't get them
Hi I hope to have a cyclocross bike soon and turning thoughts to what shoes and pedals to use, I have used spd's for mountain biking but wonder if there is a better choice for cyclocross I need new shoes anyway
All sensible comments welcome and any other comments tolerated