That's tricky and very personal. Here's a short and simple take on binoculars:

Trade-offs are basically between: size, weight, magnification and light. So it depends what you want them for.

Specifications look like this: (leaving out the more technical specs)

• 7 x 30
• 8 x 42
• 10 x 40 ....

The first number is magnification.
If it's too high you'll probably have trouble with keeping the view steady. You will probably not be using a tripod - they will be hand-held in a land rover. Go for minimum 7 and max 10. For safari 8 x 42 is great. For something like boating (due to movement) you might stick with 7x magnification. Got a steady hand? Try 10x.

The second number is lens diameter.
This translates into the amount of light the lens farthest from you lets in and thus the clarity of image. For safari specifically you are best off with a larger number here because much of your game viewing is in low light conditions: early and late in the day. That means that for safari the small compact binocs are not ideal. However you don't go on safari every day so don't get too hung up on this. You might use a small pair more often because you will be more inclined to take them with you.

Lenses:
There are two systems for binocs:

1. Double lenses: first lens magnifies, second re-inverts the image.
2. Prism. lens magnifies, prisms re-inverts image. Prisms are generally better. The image quality should be preferable.

Brands of choice:
Top three: Leica, Zeiss and Swarovski. (and the prices unfortunately match!) Leica might be more robust. Nikon, Bushnell and Steiner are good as are some others though purists will tell you that there are no "good" binocs, there are only excellent ones and "bad" ones and the first three brands are certainly excellent.

Other things to consider:
Durability, waterproofing, fog-proofing, magnifying, nitrogen-filled, field of view..... don't get too hung up on this stuff unless your needs are very specific.

Conclusion:
Decide what you want them for and consider "lugability" - weight & size. I like small compact binocs and am fine with some loss of image clarity. In fact I carry a tiny 6x16 monocular. I think it cost me about $40. Great for hiking and climbing trips. Not great for safari but then I tend to have it with me 10x as often as others have their binocs so that makes up for it. :)

• Consider those top three brands first
• Magnification: 7 to 10
• Lens diameter: as large as possible. 42 is great but you'll sacrifice that if you are going for compact ones.
• Prism system. Again- a sacrifice if you go ultra-compact

And remember: you don't have to have your own binoculars. The lodges usually provide a pair to share. Roar Africa guides do as well.