The pluses of all electric are:
1. Dash command switch(es)--have them run when you want them too.
2. Sensor override switch(es)--have them NOT run when you are fording bodies of water.
If you do two electric fans, then you should run two completely independent circuits. Run them both on one circuit, one thing fails--bye, bye head gasket/engine. This means double relays, diodes, multiple switches, and you need to add a second temp sensor somewhere, preferably one that comes on about 170 degrees, just like the bi-metal spring in the clutch fan you are discarding.