Have always kept pure spaniels, cockers and springers, but for pushing fox or whatever from big areas of cover the cross breds tend to hunt a line better, give tongue, which is handy for the fellas waiting with the shotties or lurchers (for the rabbits lol) and yet they wont go miles away on a fox like a pure bred hound would.
It all depends on what your needing from your bushing dog. But I agree for a close range flushing dog, and general pest control dog a spaniel is very hard to beat.