We've tried a few different cloth diapers, but prefolds with covers are what we've settled on as our daily go-to (overnight is a different story, I'll save a whole post for that). We've tried a variety of different covers, so I thought I'd give a rundown of all of them for anyone trying to decide:
Thirsties Duo Wrap, Size One - These were my favorites when E was a newborn. We started out with these and Blueberries, and looking back at the photos the Blueberries were just comically large on him. Even the Thirsties were bulky at first, but that's how it goes with prefolds. But they did fit his skinny little frame until he was 5 months, at which point he grew out of the rise. Amazingly, though, we were still snapping them as tight as they'd go! I especially like that they have a double gusset at the leg - this makes it much easier to keep the prefold contained, and cloth sticking out is the surest way to get a leak. They come in a good assortment of colors and a few fun patterns, and we had almost all of them. In the summer, E was often wearing just his diaper or diaper + shirt, so his covers were part of his wardrobe! The big downside is that because he grew out of the rise but not the width, he won't fit into Size Twos for quite a while. So the Thirsties are now put away in the outgrown clothing box, and we've moved on to other brands. But these were my favorite while they fit him.
Blueberries One Size - Like I said, we had these from the start, and they were huge and bulky on him at first. They continued to be a bit bulky for my liking for quite a while (I do have a VERY skinny baby, mind you), but around nine months he finally really grew into them, and at the moment (10 months) they're my favorites. They have a double gusset like the Thirsties, but unlike the Thirsties they have two rows of snaps - this wasn't so important when he was a newborn, but I'm finding it works much better than a single row now that he's bigger.
Flip and Econobum - These are the two covers made by Cotton Babies, who also make BumGenius pockets and AIOs. They are very similar, with two main differences: The Flip covers have two rows of snaps while Econobum only has one, and Econobums are made of thinner, cheaper material (which makes sense, since they're meant to be budget covers). Both come only in one-size. I didn't buy any of these until E was a few months old, so I'm not sure how well they would fit on a newborn, but I suspect they would be bigger than Thirsties Size One but not as bulky as Blueberries. I like the fit now, but the big downside is the lack of a double leg gusset. I can understand this oversight in the Flips, since really they're meant to be used with the Flip inserts rather than prefolds. We use the inserts for overnight thanks to their stay-dry layer, and the lack of a gusset is no problem then because they don't come close to sticking out. But the Econobums are made for prefolds (they even sell Econobum prefolds); I assume this is another cost-saving measure. On both brands, this makes it annoying to tuck the prefold in at the leg and leads to the occasional leak when some fabric pokes out and wicks liquid onto clothes. Now, if you want to use the Flip inserts, or prefer a pure newspaper fold (folded into thirds and laid in the cover) for your prefolds, these covers are great. But I'm considering selling mine and buying more Blueberries.
Best Bottoms One Size - I just bought one of these recently. They're very similar to Blueberries in size, although they have one more rise snap so there's more flexibility there. The main difference is that the material is thicker and stiffer - this might mean that they'll last longer, but it also makes them a bit bulkier. Probably even worse than Blueberries for newborns, but for bigger babies they're fine. I haven't tried the inserts that are supposed to go in them. They do have only one line of snaps, but that hasn't really been a problem for us.
Overall, after trying these I think that I consider the double leg gusset to be the most important feature to look for in a cover in terms of ease of putting it on and leak prevention, assuming you use prefolds. Beyond that, it's going to depend on the build of your baby - for a peanut like mine, Thirsties were the clear winner until about 4-5 months, and Blueberries fit the best now at 9-10 months. Between 5-9 months, honestly I was having trouble finding covers that fit him well. That was when I bought the Flips, Econobums, and Best Baby, and none of them fit him that well until more recently (but the Flips were better than the other two). A chubbier baby will probably have less problem with bulky covers, and a shorter baby (E is always right on 50th percentile length) will be able to stay in the Thirsties longer.
My suggestion if you're starting out, especially if the baby isn't born yet, is to start with a few Thirsties for the newborn stage (they also come in sized rather than the two-size duos), and then buy one of each of a few other brands and see what fits your baby best!