In my book, they're all the same, just different in the way they're presented. Look for one that tests all the water chemistry you're interested in testing. When you've narrowed your search, look for one with the best indicator. Personally, i don't own a kit, but i am a colorblind person who minored in chemistry in college. Its very hard to read strips that you put into a reader and pass through light. Its very easy to read the readers which you match to your indicator strip. Once again, go inclusive and easy to read. Price will follow