We work with Altec over ACOM based on a comparison of the two - probably about 2 years ago. Some reasons:
1. The functionality of doc-link seemed more complete, especially for general document and work flows.
2. The look of doc-link was more intuitive.
3. Altec seems to be very professional and organized.
4. Altec approaches projects with a consultative approach, an ROI analysis being part of the Business Process Review.
5. Altec is an endorsed partner.
6. I trust and get along well with the Altec people.
I know some would differ about my points above, but they are my opinion and feeling in some cases, and that's at times what makes us select one over the other.
Both systems are a large investment, especially if you go beyond just accounts payable, but for organizations that have the need for document management and work flow, the benefits and cost savings should justify this. I don't know of any inexpensive solutions, and am not sure they are worth it, if there is a true need. Within the CPA industry, all solutions are minimum 6 figures for firms of any size, such as ours, so the cost has not decreased over time.