I played Myth, thought it was decent. I don't really like the 'you get X units for the duration of the mission, then a new set of units' model. It seems to me to make them just as expendable as the units in an RTS game where you could build infinitely.

The Close Combat (3 being the best :P) series is, to my mind, the ideal system for units. You carry over units, they gain experience and become better with time. You don't really feel like units are expendable because a unit that's been through three operations with you is a LOT better than a freshly recruited unit.

For example, I once found myself confronted with a choice. I could trade off my old Panzer III for a shiny new Tiger, an altogether better tank, but one with a green crew.

Of course, the Russians decided that for me in the next battle. It turns out the Panzer III can't do squat against KV-1's :P