What's the difference between a top and bottom whorl spindle?
Top whorl spindles have the whorl closer to the top of the shaft, and bottom whorl spindles have the whorl near the bottom of the shaft.Top whorl spindles generally spin faster, but for shorter amounts of time.
Bottom whorl spindles spin slower, but longer. Also, bottom whorl spindles tend to be more steady and less wobbly than top whorl spindles.
Top whorls spindles are better suited for spinning thinner yarns, while bottom whorls flourish with thicker yarns. However, it is perfectly possible to spin thick yarn on top whorls and thin yarn on bottom whorls.
So which one should I get?
My advice to you would be to get both. There are some people whose favorite spindle is a top whorl, and some people who swear by bottom whorls. It really comes down to your personal preference. Some beginners like that the bottom whorls spin longer, allowing for more time to draft the wool. If you will be using the park-and-draft method (as some beginners do), a top whorl spindle might be the better choice for you. Since they spin faster, twist builds up faster than it would on a bottom whorl spindle.