I use Electric Hammer, and a GPS with Disruptor Ammo or Incendiary Ammo. It's great for tech combos. Definitely a Geth Buster, but it's decent enough for the other factions, too.
I love his melee and the combos. The damage area gets pretty wide and hits a lot of targets, which offers some advantages over Biotic Hammer, especially in terms of crowd control. Electric Hammer does DoT to multiple targets, and also primes for a Fire Explosion (although only a teammate can detonate said prime.)
I've used both, and I find Electric Hammer gives me a nice combination of offense, crowd control, and wide multi-target stagger for defense. It does less direct damage, but it has some very nice properties of its own.
Most people will definitely prefer the greater damage output of Biotic Hammer.