I have been using o.b. tampons since I was 15 years old- so for 15 years now, I have trusted and sworn by this product! I absolutely will not use any other tampon (except in a pinch!)
Speaking of pinch- that was why I started using these. There is no applicator, you simply fan out the end of the tampon with the string, then insert it with your finger. Before I used these, I was using another very popular brand of tampon that had an applicator, and I was constantly getting pinched by the applicators! Not a fun place to get pinched, let me tell you. Just try not yell out in the middle of the girls' bathroom in high school when that happens!
Another thing I like about o.b. is that I never leak with them. With Tampax and Playtex, I always leak, and so I have to wear a pantiliner as well, so I'm spending more money. With o.b. I never need extra protection, not even overnight, if I use the right absorbency.
The absolute best thing, though, is how small they are. I used to just tuck one in my bra in high school, still do sometimes. They are about 2 inches long or so, so you can hide them anywhere. No need to grab your purse when you hit the bathroom, tipping everyone off as to exactly why you're heading to the ladies' in the first place! Then, there's no applicator to flush or throw away, which is greener for the planet, and more convenient and discreet for you.
I do know some people who have a hard time getting used to inserting a tampon without an applicator, which is why I gave a 4.5 for ease of use. They're definitely worth a try!