I know this is an old thread, but having recently bought a used 500L MPW with TA 105 (a rare breed now), I can't help but to chip in.
I think it is unfortunate that TA was dropped in 500L, for the last several years, my mission has been to find a 7-seater family petrol car with 40+ real life mpg. Now finally I can rest.
My take on the car so far:
+ lively, plenty of power. If anybody thinks power is an issue, they haven't driven a TA. Elsewhere in the forum someone commented that driving TA in 500L feels like 1.6 diesel. This is true. The middle range torque is plentiful, making overtaking a breeze.
+ best mpg for a 7-seater petrol car (you can say 5+2 instead of 7 seats, but ok in our case as our 2 kids are still small). I got 40 mpg for mixed use so far.
+ superb to drive, high seating position, excellent visibility
- Weak power/torque at the start of 2nd gear (though plenty at mid rpm). Can't use 2nd gear to pull away at roundabouts/junctions even though the car is still rolling.
- Poor fabric quality on the seats for Pop Star trim. Easily stained and feels like they're skimping.
Overall though, I love the car. £30 tax and low insurance are bonuses. If it proves to be reliable, it could be the best family car we've ever owned.
Two reasons why I think TA was dropped in 500L: public perception that a 2-cyl 0.9L engine is not enough for a family/biggish car, and constant criticism of the large difference between official vs real mpg. Now, I don't know why they dropped TA in 500 as well, I thought they're perfect fit.