syntax - "each one having/has its own advantages and disadvantages"

Consider followings:

In recent years some new models have been proposed, each one has its own advantages and disadvantages.

In recent years some new models have been proposed, each one having its own advantages and disadvantages.

I used "has" but my editor changed it to "having". Should really I use "having? Why? Can you explain it from grammar point of view?

Answer

Essentially, you have two sentences:

In recent years some new models have been proposed.
Each one has its own advantages and disadvantages.

Trying to combine the two into a single sentence with a comma is awkward. It's usually regarded as an error in technical writing. There are several ways to combine the two sentences. Here are some examples:

Using "and":

In recent years some new models have been proposed, and each one has its own advantages and disadvantages.

Using a semicolon:

In recent years some new models have been proposed; each one has its own advantages and disadvantages.

Using a participial clause (which is what your editor chose):

In recent years some new models have been proposed, each one having its own advantages and disadvantages.

Turning the second sentence into a participial clause allows the two ideas to stay together in the same sentence because a participial clause functions as an adverb (or an adverbial clause). To be precise, this is called an absolute clause. Also related: choster's answer.