I don't have recommendations for you, but wanted to provide a bit more information on Archivematica.
Archivematica is not an EDRMS - an EDRMS provides a lot of additional management functionality that Archivematica (AM) does not - for starters, AM is storage agnostic. By this I mean it is not intended as a digital repository - it can be linked to one (or any storage location), but the ongoing management of stored content is outside the scope of the Archivematica project - as is access, detailed description, document creation, and other functions you might find in an EDRMS. Conversely, an EDRMS is generally not suitable for long-term standards-informed digital preservation.
Archivematica is an open source digital preservation workflow system. That is, it provides a web-based dashboard to wrap a number of open source tools together that will allow users to process digital content for long-term preservation in accordance with international standards and best practices such as the OAIS reference model (ISO 14721). You will find more information, and all the project documentation, here:
Archivematica can ingest digital content and use a set of user-editable policies to generate versions of these in stable formats suitable for long-term preservation. It will package these in an AIP as per the recommendations of the OAIS reference model. Archivematica can also generate lower-resolution access copies in more common formats for public viewing - i.e. a Dissemination Information Package, or DIP, as per the OAIS language. However, as I mentioned it is storage agnostic: by this I mean, Archivematica does have a Storage Service component that keeps track of your storage locations and what AIPs are stored where, but it does not provide a storage environment itself, nor does it provide tools for the ongoing review and maintenance of your storage locations.
Sometimes we describe it as a sausage maker - you provide the raw filling, AM can create a standards-based casing and a detailed label of all ingredients and preparation processes... but refrigeration or freezing, cooking, and serving are up to you.
Here are a couple previous forum posts where I have discussed Archivematica and its relationship to AtoM:
Hope this helps - good luck in your search!