Personally, if you're going for new drivers, I'd go for some of the digital ones. I think the AM882s have been replaced with the EM series, but I'm not 100% sure on that.
However, I'd be inclined to try the existing drivers first. I know they're pretty old technology, but a quick scan of the datasheet reveals they were pretty advanced for their time. Even if using them doesn't work out, it'll be a pretty easy swap for new drivers.

The CS-Lab controllers are good. If you need any advice about them, check out the CS-Lab board over on the Mach support forum, that's if you've not already found it.