x2 on keeping an eye on fluid levels and staying on top of the fluid change intervals.
I just had to take my 2009 sportage in for tranny work (73,000 miles). It was shifting hard and making a little "chirp" when going from 2nd to 3rd. I was convinced that the transmission was toast. The shop changed the fluid/filter, and reset the adaptive shift points in the transmission control module (or whatever it's called). The problem is gone. I had never serviced the transmission before.
The tranny in the 2nd gen sportage is a Mitsubishi F4a42, which is also used by Hyudai, Mitsubishi, and Dodge. When I was researching this transmission across a wide range of vehicles (on various car forums), I couldn't find too many examples of this transmission failing. Hard shifting and "flairing" seemed to be the most common problems, but these were caused by the control module.
Hyundai Sonatas with this same F4a42 transmission had a technical service bulletin for hard shifting. The remedy was a software update for the TCM and resetting the adaptive shift points. I pretty sure that's exactly what they did to my Sportage.
The takehome message for me is that the Mitsubishi F4a42 transmission is mechanically reliable and has a solid track record in many vehicles going back to at least 1999. Just stay on top of the service intervals, and if shifting problems pop up, they are likely to be a sensor or control module issue.