Can both units of a cluster be active at the same time? Can they do load-balancing?

Version Mar08SU 1209 and later:

Service portability, the ability to have certain services running on both nodes, is possible. While not true load balancing this does allow both nodes the ability to process messages. Please contact Sendio Support for more information.

Versions earlier than Mar08SU 1209:

Load balancing and service portability are not possible.