With any MLM, you will need to list and evaluate your own needs and
compare them against the products "out there."  Besides the technical
issues, don't forget to include the other issues e.g., (responsive and
accurate) support (both from the vendor, the licensees, and the users),
the longevity of the company, the quality and type of documentation, the
quality of the features and its platform independence, the implications
on your staff, servers, and network.

Recent MLMs that I've experienced seem to be (attempted) knockoffs (of
the ideas) of L-Soft's technology.  Yes, some have features that I wish
were in current versions of LISTSERV(R); then again L-Soft is working on
implementation of 1.8d with new features (as documented in LSTOWN-L and
other L-Soft lists) e.g., I really like the HTTP interface to list
maintenance, as well as providing a read/write list participation (via
HTTP).  At least one other MLM has a Window's-based download app that I
found in adequate.

/Pete