Any boot will work - it just depends on your "wants/needs".
Open Front Boots are meant for horses who have lazy legs over fences. So if they are to knock a pole, they'll feel it and hopefully decide to not let their legs hang over the next fence.
If your horse is a clean jumper, then I wouldn't worry about open fronts, and I would look to a nice splint/brushing boot.
Like these: Dover Saddlery | All Sport Horse Boots . Dover Saddlery | Woof All-Purpose Horse Boots.