Magnum is a solid unit but probably on the lower end as far as features. Outback is nearly indestructible and has some fancier programming options. I have no experience with Victron.
Hybird mode:
If you're running a small generator and it won't power your load the inverter will "help" the generator by providing additional power to the load. It pulls this power from the batteries which are not being recharged while doing this. So, it only works for so long. Eventually, theoretically, your load drops to where the generator can handle it alone and the inverter recharges the batteries.