Hi Faye,
I believe Giftworks is in the sweet spot for power vs ease-of-use. It's simple enough that non-professionals and volunteers can get the job done without special training and powerful enough to allow a small organization to "present"as if it had a pro staff of dozens. My consulting prectice specializes in the smallest NFPs, and I have recommended Giftworks without hesitation since it first appeared. To date, every organization I've suggested it to has bought it, and all are glad they did.
I don't think any fundraising or donor management package is compatible with SimplyCash, at least as I understand the term "compatible", because SimplyCash does not, as far as I know, support import of transaction files in any format. Giftworks with QuickBooks is a slam dunk.
Best of luck,
Joel