Having went through 1k rds of 9mm between my colt 6450 and hk 94 which I just got at the range a couple days ago, I would say definitely get the HK. I love both rifles, however, the 94 has had better reliability (only a few malfs with the colt, which I attribute to breaking in, or possibly mags, although they were brand new colts ) and has less recoil. Also the HKs arent coming around again, and certainly arent getting any cheaper.
They are both great guns, and I would highly recommend getting both, but if you can swing the hk, do it first. One thing the colt absolutely smacks the 94s as about is sights though. The only mod I have to my colt is a fiber optic front sight post, and its a beautiful thing.
BTW, I got my 94 from CDNN, who were great to deal with, and it was absolutely perfect. Im not sure if it was, but it looked brand new.
John F.