Yes, i'm getting one in April. The main difference in the Z551ML models is having a 1.8 processor compared to a 2.3 processor. The 2.3 will be priced below $300, and the 1.8 is priced around $220.
Even though it's priced around the same amount of my crappy BLU Life One X, i think the 3560 is best for me.
I will never use 4 GB, and the processor, from what i heard, is used in bursts, so there really isn't much difference in the 2 models.
They will still have 5.5 Full HD, the same 13 megs camera, and all the other goodies.
The phone will be unlocked, which allows me to keep my H2O acct. in which i pay about $20 for 90 days.