I have tried 6 different brands of liners, 3 disposable/ flushable and 3 reusable. As you are reading this, some of you are thinking these aren't even needed at all. In theory you're right, but for me to even consider cloth diapering at all, these are needed. I will compare the liners I have tried under either disposable or reusable.
Disposable/ Flushable Liners
The three brands of disposable liners I have tried are Bumkins liners, Osocozy liners, and Bummis (size large). I tried the Bumkins first because I was a newbie to cloth diapering and these came highly recommended by Amazon users. The main problem I had with these was that they came trifolded in a box. Each time I needed a new one I had to unfold them and refold them in half so that they actually fit the diaper. When I ran out of the Bumkins liners, I decided I would try liners on a roll instead because that seemed easier to use. They are much easier to use! I chose the Osocozy brand because they came highly recommended by Amazon users as well. At the end of that roll I chose to go with another brand to continue my research and experimenting into the world of cloth diaper accessories. I decided to go with Bummis because they were highly rated and another blog recommended them (if I remember correctly). It wasn't until I tried the Bummis that I realized I wasn't truly happy with the quality of the other 2 brands. The first 2 brands stuck to my son's skin more and also had more trouble staying in place (bunched up). Especially the Ocosozy brand seamed to fall a part. For now, I plan to stay with the Bummis brand.
The three brands of reusable liners I have tried are Bummis fleece liners, Kushies fleece liners, and Kinckernappies fleece liners. I tried the Kushies liners first because they were available through Amazon Prime. I can see why these are poorly rated. First of all, they are cut strangely and are short. I have to use 2 in my son's diaper (on the rare occasion I actually use them). They don't stay in place well at all. If I had to do it all over again I would never have purchased the Kushies liners, but that purchase was before I found a local cloth diaper store ;). The next liners I bought were the Knickernappies. I found them at my local cloth diaper store and bought only 4 at first to try them out (then quickly ordered 10 more ;). These by far are my favorite reusable liners to date. I hope to get more of them soon. What's nice about these liners is that they are a nice length, which means they stay in place. They're also made of a sturdy, but soft material (so nice next to baby's bottom). Having tried 2 fleece liners and the Bummis disposable liners, I decided to try a 3rd reusable liner, made by Bummis. These are my 2nd place reusable liners, because they are shorter than the Knickernappies and the material is more flimsy than the Knickernappies.
In each of my son's diapers I like to use 1 reusable and 1 disposable liner. The reusable liner helps to protect the diaper from stains so that I can use them possibly for a second child in the future or donate them. The disposable liner make cleaning up poopy messes oh so MUCH easier ;). I'm so thankful for liners!