I know the 3rd edition has always been the go to reference guide. Are there any others that compare or that are just as good for attributing them??
If you can find a copy (it's out of print) then I find The Ultimate Guide To Attributing Bust Half Dollars by Glen Peterson to be easier to use than Overton. There are also a couple of online sources that work well. CoinZip (you will need a free account) http://coinzip.proboards.com/ and Dave's Bust Half Dollar Site http://www.maibockaddict.com/
I have never seen the third edition, but somewhere I read the pictures were better and nicer than the 4th or 5th edition.
I agree , When I purchased my book 7 years ago it was $125 . It is much easier to use & I'd say 80% faster to attribute. Well worth today's asking price of about $100
Here it is for sale for $93 http://www.wizardcoinsupply.com/the-ultimate-guide-to-attributing-bust-half-dollars.html