Snap diapers and Velcro diapers each have their own advantages, so it all depends on your own needs and interests as to which kind you purchase. Let me give you the run-down on each kind.
Pros and Cons of Snap Diapers
I personally think the most noteworthy advantage of snap diapers over velcro diapers is the fact that they seem to hold up much longer. Whether you are using a diaper cover with prefolds or fitteds, pocket diapers, or all-in-one diapers, cloth diapers with snap closures stay looking nicer for a longer period of time. If you plan on recovering some of your investment, snap diapers will likely re-sell at a better price.
There are a few drawbacks to snapping diapers that you want to make note of. For one, snapping diapers will cost you a few more dollars than other styles. On average you can expect to pay about $2 more per diaper. The other thing that sort of stinks (pardon the pun) about diapers with snaps is that you cannot customize the fit nearly as well as you can with Velcro closure.
Difference Between Velcro, Aplix, and Touch Tape
The first thing that I want to mention here is that though Velcro sort of has become a generic term that covers all sort of hook and loop closure fasterners, you may also see cloth diapers advertized as fastening with Aplix. I would say that Aplix has a softer texture, is stronger than Velcro, and is less likely to be abrasive to your baby's skin. Touch Tape also seems to be stronger and softer, and you'll likely find it to be the least expensive of the three kinds.
Pros and Cons of Hook and Loop Cloth Diapers
I see two advantages to hook and loop closures worth mentioning. One, they are cheaper. I like saving money, so cheap is good. The other advantage is that you can customize the fit much better than snapping diapers. You can tighten the waist, angle the sides to account for skinny or chunky thighs. I think you can get a much better fit with a velcro diaper than you can those with snaps.
Really, I find the biggest drawback to diapers with hook and loop closures is that after a while, they just do not look as nice. Even with laundry tabs to fold down the Velcro, I always find that it snags on other diapers or itself. Fuzz balls and hair collect in the scratchy side, and often it seems to curl up. Not only have I found these diapers to wear out quicker, it also will effect your resell value.
My advice would be to build your cloth diapering stash up slowly at first. Buy a few of each kind of diaper and see what works best for you and your baby.