Depends on whether you want the iOS operating system, Windows, or Android, and what other features (if any) you might want to go along with those tablets.
In other words, I suggest you figure out what software features you need and whether the operating system is important to you, rather than focusing on the hardware. The physical hardware is the most minor issue of them all.
Disclaimer: I'm a die-hard Android enthusiast.
Do not be swayed by the idea that "high prices equals high quality." This is a common marketing practice, and is known as "perceived value." What it means is that when an object is assigned a high price, people will mentally try to justify that price, and will conclude the object must be of better quality than a lower-priced object.
While that may sometimes be true, often it is the case that the lower-priced object is the same (sometimes even better) quality. A common example is "store brand" grocery items. They are often made in the same production plants, using the same ingredients, equipment and employees as the "brand name" products. The only
difference may be in the outer packaging. But because the "store brand" is less expensive, many people assume they are of inferior quality... and use that assumption to justify paying extra for the "brand name" when they could have obtained the same item for less
simply by purchasing the store brand.
This is not to say that less expensive items are always
the same quality as more expensive items. Sometimes it's true that higher price is the result of more expensive / higher quality ingredients or components. But not always. It's equally common for a company to deliberately price an item higher than necessary to take advantage of that "perceived value" and position themselves higher in the marketplace.
And in the case of tablets, there are a number of fine "brand name" quality alternatives, many of which are somewhat to much less expensive than the iPad. So unless you need some feature or app that's only offered for the iPad, you might do well to at least consider other potentially more cost-effective alternatives.
You say you're going to use them for presentations. Will you have a need to connect to a projector, or are these presentations going to be totally standalone? If you want to connect to a projector in a corporate environment at any point, you might be better served with a Windows 8.1 convertible that can also function as a laptop.
Android tablets offer many of the same features and can offer equal visual quality as iPads, and are often available at a more favorable price. But you'll be running Android, not iOS, so if the Apple operating system is important for you for any reason, you'll want to stick with the iPad. Otherwise, Android tablets may be a price-effective alternative.