What's the difference between deglazing with an alcohol or non-alcohol?

Deglazing with any liquid, alcoholic or not, will have different result in regards with flavor but there is no way to say which one is better than the other, it's just a question of personal taste.

Using different liquids, alcohol, juice, water, stocks, broths, will help remove bits and pieces from the bottom of the pan.

As Max said, much of it's personal taste as for which is "best", but to explain it a bit more:

Most types of alcohol have a flavor themselves, so they will change the flavor of whatever you're deglazing. Vodka or other highly distilled alcohol have little flavor on their own, but it may still change the flavor of the dish by bringing out alcohol soluble flavors from the ingredients.

It also evaporates more quickly than water (although it doesn't necessarily cook off completely), so it allows you to deglaze the pan, but then cook it back to almost dry fairly quickly, to build up the next layer of fond. This can affect how much you end up cooking the other ingredients in the sauce, and the total time to completion.

The acidity of the liquid can also affect how things cook -- more acid will cause things to brown less and stay firmer, so changing the deglazing liquid can alter how other ingredients taste and the final texture beyond in some subtle ways.

The only thing that I can think to recommend avoiding is very sugary liquids in small amounts when your pan is really hot -- the water evaporates quickly, and then the sugars start to brown quickly, and you have to deglaze again before it burns.