I understand a lot of the work on the ACA630 was done by hand and made it more expensive to produce, a shame really as it is truly the best option for an A600 by a long way. Sadly second hand prices have reached such heights that it's now cheaper to buy an A1200 and Blizzard 1230! You'll even have change for some other goodies!
ACA620 is actually a pretty decent spec for an A600 since really you wont get the most out of the ACA630 due to the limitations of ECS (i.e a 16 colour workbench still runs quite slow on an A600 even with ACA630)
The 620 still has MapRom and 11.3mb is still enough for most ECS WHDload games, the 16mhz 020 gives an 8 colour workbench a nice boost even at 800x600 with the Indi ECS which is what I run my A600 with now since selling my ACA630. Of course I miss the 630's power but the 620 is enough for me...
