My personal preference is for zip ups, because pull-on boots are just too much trouble to get on and off for my liking.
In your price range, you should expect that you will need to replace the zippers in any pair of boots you buy if you choose zip ups. One of the ways that bootmakers cut costs to sell in the introductory price range is by using cheap, plastic zippers. They tend to break almost immediately, but once replaced with a quality metal zipper, you're good to go.
I have been pretty impressed with the quality of Hispar boots for the price, but I would caution against buying brown if you can only afford one pair, because if you're going to do any showing, you're probably going to wish you had black boots. Not that you *couldn't* show in a brown field boot, but black is much more traditional.