Many considerations
If you are looking for mass produced holsters there are several reputable companies - Don Hume, Galco, Bianchi, Safariland. These are generally a less expensive than custom holsters. For OWB in a small frame revolver the Bianchi Black Widow is my choice in this price range.
There are a number of reputable custom holster makers who can make most anything you want. FIST
http://www.fist-inc.com offers a large variety of styles and options. They make a good product at a reasonable price in both leather and Kydex.
Whatever brand you choose there are some features to look for, and to stay away from. Stay away from soft fabric and stay away from metal belt clips no matter the brand name.
Look for:
Leather or Kydex for OWB but I find Kydex too unforgiving and uncomfortable for IWB.
Belt slots for OWB and snap straps for IWB that are placed fore and aft the gun, not over or behind the cylinder.
The mouth of the holster needs to be stiff enough to stay open when the gun is removed. A reinforced mouth, especially for IWB, is usually necessary to accomplish this.
A thumb snap is a desired feature to assure retention. You are not required to always use it (although I recommend you do) but it is always there for times you will wish you had it.
Shop thoroughly until you drop - the money!