On Diaper Closure Systems:
Cloth diapers don't come with the little sticky tabs that disposables have, so you gotta' have some way to hold those babies on your baby. Some diapers have their own closures already included, others require that you use a separate closure or diaper fastener.
Some options include diaper fasteners, ranging from the good-old long-familiary safety pins to fancy "grabby/stretchy" options such as snappis (TM) and boingos (TM).
Other diapers come with closures on them: velcro/aplix and snaps are most common, though you can also find some that tie on or even button on. All of these different closure options have benefits and drawbacks, and like with all things parenting - it really comes down to personal preference and what works for your family.
If you are comfortable using pins or snappis than I would definitely recommend getting diapers without closures when possible. You get much greater sizing flexibility since you can fold down the rise to exactly where you need it and close them at the waist exactly where the best fit is. They are also simply the CHEAPEST option, and may allow you to avoid diapers altogether since you can pin, snappi, or boingo on just about ANYTHING absorbent: t-shirts? sure. Socks? Why not? Towels and washcloths? You bet! They may also make some diapers reversible, allowing you to get two looks for the price of one. Throw some extras in your diaper bag and you will NEVER not have a diaper for your kiddo (even if you have to literally use the shirt off your back).
However, if someone other than you (hubby, grandparents, daycare) will be changing many of the diapers, you will want to be sure they are ok with pins or snappis too, most prefer velcro or snaps. Or if you have arthritis or some other difficulty with your hands or fingers, or you find your baby too wiggly for a good fit that way, you might prefer something with
closures built in.
Hook and Loop Tape, (also called Aplix and Velcro which are specific brands) makes diapers go on just like disposables so it is very familiar to people, and it does allow more accurate waist adjustment than snaps since you can adjust it infinitesimally. It is very quick and easy to use and can be great for squirmy babies who hate to have their diapers changed.
On the down side, it does wear out over time (generally 12-18 months) and has to be removed and replaced. It also has a tendency to snag on EVERYTHING in the laundry, even WITH fold-back laundry tabs the velcro still finds ways to grab things at the edges. In addition, some kids readily figure this stuff out and LOVE to take off their diapers (whether full or not), and hook and loop makes this an easy and fun game for them.
Snaps are a relatively new cloth diaper closure option but have the benefit of being attractive and
simple. However, they do limit sizing flexibility somewhat since they adjust incrementally. These are probably the most durable option, and if you want to use the same diapers on multiple children may be your best bet. Pins, snappis, and boingos will wear out the corners of diapers over time. Velcro will need to be removed and replaced between children, but with high quality polyacetal resin snaps (such as KAM) your snaps will likely outlast the fabric of your diapers itself.
Another benefit is that because there are only a few options (three that I am aware of at the time of this article) for purchasing snaps nearly all snaps on most diapers made today are interchangeable. They can also usually be replaced if you find you do encounter one that doesn't function properly for some reason.