I wouldn't be scared of the Soul's reliability... it's using a proven powertrain combo that many other Hyundai/Kia vehicles have used in the past few years. And as far as I know, the SX4 has been pretty reliable so far.
With that said, I really like the SX4, but would need to test its new-for-2010 CVT transmission before buying one...
If you want AWD, then it's a no brainer.
Both great little vehicles, can't go wrong, IMO.