Mine went up about 5% (Circle C area). I'm going to protest it, but really its not that far off from the sales I've seen in this area.
As for protesting, unless there is something really weird about your property, or just not a lot of comparables, you're wasting money using those services. Takes less than an hour of your time typically.
1) Request the hearing (done online) and go for the absolute latest. You want everyone else to do the majority of the work first.
2) Find comps, use redfin or similar, that justify the price you're trying to get down to.
3) Go to the informal hearing, have them re-run the matrix. You get the benefit of everyone else that has already protested their taxes and gotten them lowered. Chances are that will be as low as you're going to get if there's any type of robust market in your area. If not, present your comps. They may accept them, they may not and you have to go to the formal hearing. I've never had to do that though.
4) No profit, but you'll need slightly less lube at the end of the day.