Corrupted files are unacceptable. Memory capped errors are familiar to me from Excel – I know it well. Excel 2k7 is more prone to throw up and crash but its recovery works perfectly so far: 2k did not crash but I learned to walk away sometimes for a while while it ‘froze’ in calculation mode. (it stopped screen updating ’tis all). But I’d say that Excel 2k7 is equivalently stable, even if it handles it differently – and the extra rows and columns are WELL worth the slight discomforts of trying to find my familiar things.
For Search/Replace functions, I’ve always dropped down into text: usually with NOTEPAD++ but that’s a luxury I have because I’m not dealing with complex documents, just big text files.