Some are excellent and some are junk. Some work great with only higher Kinetic energy setups, some will work well with Lower KE setups. It really depends on what your looking for and your setup. Rocket heads in general are good. They fly well and open quickly. The blade sharpness should be better however. Practicing with mechanicals can be done, and depending on the model you can use dental floss to tie down the blades. It's really hard to answer your question without knowing first the heads your interested in, and then what the specs are for your setup. Draw wieght, length, arrow weight, speed, bow make and model etc. You can visit my website www.broadheadtests.com and get some info but we really need to know more about your setup before we can offer good advice.