BHinSanDiego, I JUST saw this posting of yours. Sorry for the delay.
There are surprisingly few (surprising to me) shuttle services to/from the Madrid airport, probably due to the licensing, fees, and maybe even trade union issues so your options are few.
AeroCity is a well-known, established service in Madrid and has been reviewed here many many times. I've even taken them on occasion. Good service at good prices. Remember, though, that it's a shared service and that's how they keep prices lower. Yours may be the first stop or the last stop along the route.
Saludos, MadridMan
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