Yeah the AI-3 isnt bad but if you want a cheaper option id go for the fostex vc-8.. only about 80-120 on the secondhand market.. most people seem to use these on thier 828s or digi1's etc..

The main difference is vc8 is a half rack and ai-3 is full rack & vc8 uses phono connectors whereas the ai-3 has balanced 1/4" jacks - but there is a good difference in price and i dont know for sure but i can imagine the converters being better in the fostex anyway so its 6 to half a dozen really ;)