Oil vs water stones

[Barmaley]

Is there a general idea about performance of oil and water stones? Here I have a couple of questions:

a) Why some stones like water and some oil. Is it based on the type of abrasives?
b) Are oil stones better in general?

I personally prefer oil stones since they are less messy. Any recommendation for a budget 1200-2000 oil stone?

 

[Ourorboros]

It's the binder. With Shapton Glass, SiC, and aluminum oxide you can use either. The abrasives themselves don't care.
Define "better".

 

[FortyTwoBlades]

Oil is usually used on stones with harder bond strength as it is the most lubricating, and so reduces wear on the abrasive to keep it cutting effectively. Vitrified bond water stones are usually done at a softer bond strength and can be used with oil. Urea-formaldehyde resin, used as the binder in "splash-and-go" type water stones, however, should only ever be used with water because the binder is water-soluble and is otherwise much too hard to properly shed in use. Using those stones with oil will cause spots penetrated by the oil to be unable to soften with water, and so creates permanent hard spots.