Basic Information: I believe this is accurate and enough to get a general idea while looking
Montero(US)/Shogun(UK)/Pajero(Everywhere else) is the full size SUV and all are 4WD.
Gen 1: 1982-1991
2 and 4 door versions
Inline 4 and 3.0L V6
5-speed Manual or 4-speed Auto
Rebadged and sold as Dodge Raider in US too
Solid Rear Axle
Independent Front Suspension
Body on Frame
Gen 2: 1992-1997
Only 5 door versions in US
3.0L and 3.5L V6 engines
4-speed Auto
Super Select 4WD
SR trim has factory rear air locker
Solid Rear Axle
Independent Front Suspension
Body on Frame
Gen 2.5 (Gen 2 widebody): 1998-2000
Only 5 door versions in US
3.5L V6 engine
4-speed Auto
Super Select 4WD
Winter Package has factory rear air locker
Solid Rear Axle
Independent Front Suspension
Body on Frame
Gen 3: 2001-2006
Only 5 door versions in US
3.5L (01-02) and 3.8L (03+) V6 engines
4-Speed Auto in XLS (01-02), 5-speed Auto in Limited and 03+
Super Select 4WD in XLS, Super Select 4WD II in Limited and 03+
Hybrid LSD in some vehicles from 01-02
Traction Control used in 03+
Independent Rear Suspension
Independent Front Suspension
Gen 4: 2006-Present
Not available in US
Montero Sport (US)/Challenger (Everywhere else)
Gen 1: 1996-2008
Mid-size SUV
2WD and 4WD models
3.0L and 3.5L V6
4-speed Auto
Solid Rear Axle
Independent Front Suspension
Body on Frame
Best one for your wife is a Gen 3 Montero. Comfortable and easy to drive. 03+ with traction control are more desirable. Any Gen 3 with 5-speed can be driven in AWD (4H) on road for added safety. Montero Sports are a renamed Challenger SUV. Not bad vehicles, but not the same as a Montero/Pajero. No idea why they used this naming convention in US.