I have noticed that all the big tourney lists aren't bothering with immortals at all.

My unit:
Zandrekh Leading
10 Tesla Immortals
Plasmancer
2 Cryptothralls

I just played a game against Dangels.

Turn 1 Zandrekh rolled mortal wounds.
I moved up and shot a unit on an objective. 8 mortals plus 8ish overflow wounds. WIPED
His turn he moved up a new unit in range of the marker. Overwatched it. 9 Mortals plus change. WIPED
He moved a unit in and shot at them, killed the 2 thralls and 4 immortals. I returned fire with the leftover immortals. 7 Mortals plus wound change. WIPED.

I am aware that Big Z's ability is a chance game but 2/3 times it's very good and it allows a Vecht to be used on the table.
I highly recommend trying this combo out.