I just recently unlocked both Krogans (in one single Premium Spectre Pack) so I haven't been able to enjoy the melee-tastic experience until now.
I had a ton of MSP to burn through when I bought the game so I spent them on Spectre packs hoping to unlock an Asari Adept (easily my favorite class from the demo) ... after about 15 Spectre Packs (some with MSP, some with credits) I couldn't unlock another species to save my damn life. I did however net an N7 Valiant from one. Too bad I suck at sniping.
I got both the Asari Adept and a Krogan in my second Premium Spectre pack - guess that was pretty lucky. I still don't have a Turian, Salarian, or Quarian though.
I played as the Asari Adept last night after promoting my initial Human Male Sentinel. I'm not used to being so weak (low health, shields, and melee) so it is taking me some getting used to. I guess I need to get that Statis bubble unlocked ASAP - I've seen people use that pretty effectively.