After a sabbatical I have made it back to working with hide glue. I have done some testing and have had some utter failures and great successes. Working with this glue is one of those things you have to experience for yourself. You can read all you want but until you put glue to water you won't "get it." That being said I have a few things you should look out for if your going give this glue a shot...
As far as I'm concerned here is the holy trinity of hide glue; Viscosity, Temperature, and Age. The glue has to be thinned correctly, wood and glue have to be at the right temperature, and the glue needs to be fresh (1 week life span if stored in fridge). Sounds complicated, huh? As it turns out its really not that bad.
Viscosity - The hard part is how do you know if the glue is at the right consistency if you have never used the glue before? Proper measuring seems to be the best method. My 251 gram strength glue needs to be mixed at a 1 part glue to 2 parts water by weight. This led me to steal my wife's dieting scale out of the kitchen (thats between me and you). If you use the same container each time you might be able to do this by sight, or even put lines on the side of the jar to indicate how much glue and water. After you have been doing this for a while you will be able to add water on the fly and get the glue to where it just looks right.
Temperature - The glue needs to be at full temp before use (about 140 deg.) If its cold in the shop you will also want to warm the wood being glued. You can do this however you want; heat gun, hair dryer, sit wood by the stove, etc. If the wood is to cold it will start to gel prematurely and you'll get to scrape the glue off and try again.
Age - To see if your glue is still good heat it up and place some between two fingers. Wait for it to start to gel and separate your fingers. You should see webs of the glue form between your fingers. You want nice long webs. From my little experience the webs get weaker and break off easily when the glue starts to age. It will look like you have small hairs on your finger. At that point I would toss it and make up some new glue. I did a little test on new glue vs glue that was 4 days old and the old glue was much weaker and didn't seem to cure fully.
Is all of this really worth it? Absolutely, I'm sold. If I start form scratch it takes me about 2-2 1/2 hours to make a new batch of glue that is ready to use. For me that is acceptable. I just get my glue started in the morning and work on the project. By the time I'm ready for the glue it is generally ready. Hide glue is much cheaper than other glues. For about $10 you can buy a bag of glue that will last you a long time. How many times have you bought at bottle of PVA and let it set for a while and then wondered if it was still good? If your like me, you do that every spring. Hide glue will last forever in its pellet form. Just keep it stored in a cool dry place (thank you Ziploc).
PS. Shout out to all guys on WoodNet forums for pointing me in the right direction on getting my viscosity right.