the best IDE controller on the Amiga has to be the Buddha from Individual Computers. I have used these in A2000, A3000 and A4000 without incident, ever - they are great, compact and very easy to use, and come with software to help even speed up IDE access on the card. And they are inexpensive, especially when compared with the scarcity and increasing price of any other zorro card out there (especially ethernet) these days.
here's the page for the card
http://www.jschoenfeld.com/products/buddha_e.htmyou can likely find a used one in eBay, or get a new one from Software Hut, Compucare or Mr. Hardware, depending on where you live in the USA (assuming you live in the USA).
good luck!
kevin orme
amiga university
www.amigau.com