As already said the 040 is about twice as fast as the 030 with 50% of the clockspeed and as also already said the Apollo cards are not same high quality as the Blizzard card.
What you also have to take into account however is that a lot of stuff is 040 incompatible and will crash, where's the 030 is almost 100% compatible with just about anything (060 have better compability than the 040 but still not as good as 030).
I personaly have both a Blizzard1230 and a Blizzard1260, the 030 is in my backup machine and mainly to keep everything compatible wheres the 060 is in my "Black Widow" project. The Blizzard1260 have a fallback mode so in case it doesn't run on the 060 you can always bump it down to 020.
