Like "I've never used one and I've been diabetic 18 years. I've heard people that dislike it and enjoy it . I think it's up to the individuals preference. I use the prefilled insulin pens and I like them and I also count carbs. I just started recently but I have a cheat sheet that for every 10 gram of carb I take 1 unit of insulin. However everyone's body is different! Good luck with your decision "