I have a 2004 with 71,000 miles.
Other than usual maint and fluid changes, the only issue I have had so far is the Idle control valve went bad.

I am hoping to get feedback from all owners to get a better idea of usual issues with the van.

 

Current mileage: 85K miles

Major Service History (omits oil changes, air filter replacements, tire replacements, brake services)

12 2002 00K Purchased new
07 2005 28K PCV Hose and Fan Module recalls performed
01 2006 36K Flushed transmission fluid
02 2007 51K Flushed power steering fluid
03 2008 67K Replaced Bank 1 pre-cat 02 sensor
08 2008 74K Flushed transmission fluid
09 2008 75K Replenished coolant additives
11 2008 77K Adjusted coolant pH to 8.0
11 2008 77K Added Lubeguard Red to transmission (for occasional shift flare)
11 2008 77K Replaced Bank 2 pre-cat 02 sensor
12 2008 78K Replaced failing PCV hose with 3rd generation Mazda part (AJ51-13-89YB)
12 2008 78K Replaced spark plugs with Autolite APP104 (highly recommended)

My MPV runs like new. I am still using the original coolant (with additive replacement and pH adjustment) which I trust more than aftermarket coolants. At some point, I may buy expensive Japanese OEM coolant for Mazda/Honda/Toyota/Nissan as a replacement.