Aluminum machine shop (for OpenPCR)

Hi all,

I'm looking into having aluminum tube blocks machined for OpenPCR. We need a shop to make both 3 or 4 prototypes with about a week turn time, and would like to have that same shop also scale up to 25 or 50 parts with a turn time of 20-30 days.

After some google searching I submitted our design to First Cut and Zero Hour Parts. Both of them are great for prototyping, they have a 5 day turnaround time at ~$100 a part. However, scaling up doesn't save money, still around $70 a part.

eMachineshop on the other hand can hit 1/3 of that price in the quantities of 25-50. But their prototyping is slow and expensive.

My question is, what machine shop would you recommend? Do you have experience with a shop that does both CNC prototyping and small runs for good prices? Are my concerns of "sticking with the same shop" undue, can we switch shops without problems?

Thanks!
Tito