.. are all valid, but some of them - when speed (rapid) is really important - , such as requesting "ultra-thin (~5-mil) outer layers" for a rapid turn prototype should not be required. Of course, if you plan to get the production boards from the same source, get it 100% the first time. Also see below re production boards.

Also, I have no doubt that concerns such as "If their tolerances are too generous," can be very valid re the "Earl Schieb" rapid proto places, but I have no experience in using such places. I stick to the rule "who is to produce is to proto".

In general I would say: If you plan to produce, get the protos from where you will get the production. I have had 'unpleasant' experiences working in places where the road from design to proto and the road to production was not the same.

Now, if getting a few protos is really "the" production, then, by all means, try one of the "Earl Schieb" places, the price can not be beat.

Re BGAs: i would never dream of using a BGA unless using a contract manufacturer that guaranteed the product.

One final recommendation: since Richard post a very large experience with "produced protos" (the proto IS the product) I would follow his recommendation.

Erik

For foreigners: Earl Scieb is know for advertising "I will paint any car any color for $99" (more today). An Earl Schieb paint job is easy to recognize.