I have a 97 Previa from new, best MPV IMO...
Firstly, mine seats 8 (it has a bench in the middle instead of two separate seats), I know of no other MPV that has this configuration - for some reason they are all 7 seaters in this range. But you may not need the 8 seats anyway so not sure if this is relevant to you.
Secondly, it has a unique flat-4 engine (See Alfarsud and Subaro...) which is located under the front seats leaving more space inside - this is the only MPV in this range where you still have room for luggage behind the rear seats even with all 7/8 seats open. But keep in mind that the 2000 onwards models are a little smaller than the older 91-99 models.
Thirdly, as said, it is a Toyota... in the 10 years we own it nothing ever went wrong with it - all it need was routine servicing. Oh, and we did the clutch and brake discs once.
The downsides....:
No DYI... the engine is right under the front seats and not accessible, even relatively small jobs such as changing the spark plugs are an engine-out job, and therefore can not be really done on the drive (remember the engine comes-out from underneath the car...
Then there is Toyota dealer pricing.... in London it's 95 per hour, I think that only Plumbers and Brain Surgeons charge more... and Toyota official work times are also ridiculous, like 1.25 hour for changing brake fluid (realistically 30 minutes job on the drive, 10 minutes at a properly-equipped garage..)
On another note, there are also Japanese imports - the Lucida and Emina - they are generally better equipped with toys such split aircon (rear/front) and dual sunroofs, this is OK but the Lucida is narrower than the standard Previa.