WHich is better? dry active or compressed yeast and what are the benefits of the better one? I am currently using compressed yeast but all the recipees I have looked at recently call for dry active yeast

Here’s the down and dirty on yeast;
Compressed yeast is fine, it is the standard to which all other yeast types are measured, and it is still the standard of the baking industry, however, it does have its short comings, it must be kept under refrigeration at all times. It has a maximum shelf life of 30-days, but you can see a measurable loss of activity after as few as 7 to 10 days in your cooler. Contrary to popular belief, it doesn’t need to be suspended in the water, it can be simply crumpled right on top of the flour and it will mix in just fine. Active dry yeast (ADY) must be pre hydrated in warm water (100 to 105F) for 10-minutes before you add it to your mix. It has a shelf life of about 6-months for the unopened package, and it doesn’t need to be stored under refrigeration. Once opened, the package should be used within 3 to 5 days. The biggest drawbacks to ADY are the need to pre hydrate (seldom done correctly resulting in loss of yeast activity), and its inherant inconsistency. Remember, this type of yeast was originally intended for use in the home. Lastly, Instant Active Dry Yeast (IDY). This type of yeast is quickly becoming the preferred yeast for many pizzerias. It doesn’t need to be pre hydrated, meaning that with few exceptions, you can just toss it in your mix right on top of the flour and begin mixing. It has a long (1-year or more) shelf life for the unopened package, allowing you to purchase in bulk if need be. It can be stored at ambient temperature, and once a package is opened, it should be used completely within a week (7-days). Leave the IDY in its original bag and just roll the bag down onto the yeast and secure with a rubberband, its that easy. If your total mixing time will be less than 4-minutes, the IDY should be pre hydrated in water at 95F (this is VERY SPECIFIC). Use of a higher or lower temperature water will deleteriously affect the yeast activity.
How much to use:
The conversion is as follows: Compressed yeast (16-ounces) : ADY 8-ounces : IDY 6.5-ounces
Another way to look at it is to find the amount of ADY to use to replace compressed yeast, multiply the amount of compressed yeast by 0.5 and to find the amount of IDY to replace compressed yeast multiply the amount of compressed yeast by 0.4 and to replace ADY with IDY multiply the amount of ADY by 0.8.
Tom Lehmann/The Dough Doctor

I looked at the IDY option a while back. Since we use about a 2.5 minute mix and I have zero confidence that my crew will get the temp right consistantly, we stuck with compressed. The shelf life has not been an issue for us, we just keep a few pounds around and order as needed. Once in a while we throw some out, but at $1.20 a pound throwing out a half pound once or twice a year doesn’t hurt too much…

Also, we use water a cold as we can get it anyway in our recipe so adding warm water for the yeast kind of conflicts with that approach.

I agree totally that compressed yeast (CY) is probably the best for your specific application. Keep in mind though, that while you do need warm water to pre hydrate either of the dry yeast forms, the amount of water is very small compared to the total amount of water added to the dough. For example, we normally suggest hydrating the yeast in at least five (5) times its weight of water. This means if you were using 40-pounds of flour, the amount of dry yeast would be between 2.5 and 3.25 ounces (depending upon the yeast type) so we’re only talking about roughly 12 to 16-ounces of warm water out of about 22.5-pounds total. I make mention of this because I run into so many operators who erroniously think that all of the water has to be warm when hydrating one of the dry yeast forms.
Tom Lehmann/The Dough Doctor

To answer your question, which is better, ADY or compressed yeast? When correctly used, that are both the same. The biggest drawbacks to ADY is the need to pre-hydrate the yeast in warm (100 to 105F) water before using it. Rarely is a thermometer used in this step, and it results in inconsistent yeast performance, which many like to blame on the “weather”. Also, ADY has a history of some inconsistencies in performance, and this is due to the fact that it was never intended for commercial use, instead, it was intended for household use. To convert from active dry yeast (ADY) to compressed yeast (CY) just multiply the CY amount by two (2). So, if a formula calls for 1.5-ounces of ADY, you would need to use 3-ounces of CY to replace it. Do not confuse ADY with instant dry yeast (IDY). They are entirely different products in the way you add them to your dough. IDY is best added directly to the flour, without any need for pre-hydration. In some instances, where the total dough mixing time is less then 4-minutes, even the IDY must be pre-hydrated. In this case, the IDY must pe placed into a small portion of warm water at 95F. If the water temperature is off by as little as 5F, it can affect the yeast performance by as much as 5%, and it gets worse as the temperature error widens. To replace IDY with CY divide the IDY amount by 0.4 to get the amount of CY to replace the IDY with. For example, if 6.4-ounces of IDY is specified, Divide 6.4 by 0.4 = 16-ounces of CY.
I hope this answers your question.
Tom Lehmann/The Dough Doctor