This is a very mature technology. Therefore, when a particular model offers special advantages, you can expect these to be offset by corresponding disadvantages, either in performance, convenience, or price. Choosing the right instrument for your purpose is a matter of choosing where to compromise. The following guidelines will help. The first number is the magnifying power.
Beginners usually assume that the higher the power the better.
The bigger the objective lenses the brighter the stars, and here the astronomer should compromise least. Most astronomical objects are hard to see not because they are small and need more magnification, but because they are faint and need more aperture. Center-focus binoculars are convenient for birdwatchers and others whose targets often shift from near to far. But astronomers don't need this feature. With these you focus each eyepiece separately.