As said, I have been around the block or two and see some interesting changes in the system integration business. First it seems everybody wants to be in healthcare and they all say "well we do wireless". Second, the next thing is that they can do everything, WLAN, DAS, medical device testing, you name it.(oh yes we can pop popcorn..also!)
One of the most recent engagements that Integra Systems, Inc. was involved in was analyzing a "concept" that a system integrator proposed. Due the nature of construction the integrator proposed that access points should be used above the ceiling and outside the inner rooms of a scientific research facility. Being the type of work conducted...they did not want the APs in the rooms. Walls were 10" thick concrete with re-bar with multiple layers of epoxy coating. Their proposal was to use standard Cisco AP(s), and affix to them 6dBi and 12dBi directional antennas and max out the power settings on the APs. I just laughed when I heard this. The thought process was well as long as I can get -65dBm, I am good to go. They did not know about co-channel interference which with NO applications was around 80%. Think of engineering a point to point outdoor 3 mile link and pointing this at a steel door 4 ft away. Oh yes, it violated the manufacture's specs, EIRP exceeded FCC limits.
In evaluating integrators it is important to understand not only their certifications; but actual real life wireless experience. Finally the firm needs to have a large enough footprint that is scalable for support. For instance if a medical device company needs to accomplish ten different implementations in ten states...can they do this? Talk is cheap...when you have to execute. If for example if they say they can implement DAS (Distributed Antenna Systems), do they have folks on staff that can drive www.ibwave.com and have people in house with the appropriate FCC certifications?
The situation described above with the AP(s), directional antennas, etc., was the funniest thing I have ever seen in regards to indoor wireless. Quite comical (but serious), that the integrator actual told the customer everything would work fine for wireless voice over IP.