Hi,
I've had a C70 2.0D powershift and now have a C70 D5 Geartronic.
The powershift was a very nice smooth gearbox, the 2.0D is a bit underpowered for a heavy car but adequate (they often put out about 150bhp on a dyno so a decent cruiser). I could squeeze 50mpg on my commute.
The 2.0D engine has its issues but they are well documented on here. I had this engine in a V50 also, and it was excellent. Biggest issue for me is the powershift 'box.
Mine went wrong and would have needed serious work (£2K plus) to fix, so it got moved on! Lots of stories of powershift unreliablity compared to the geartronic. Don't think I'd take the risk again, especially when mileage gets high.
You can read my experiences here: -
http://www.volvoforums.org.uk/showthread.php?t=217685
The D5 is a different beast. Loads of torque suits a heavy car, so it feels quicker than it is. Geartronic is a good reliable gearbox, not the latest technology, but more than good enough for a big cruiser. Slow off the line, but when moving it can keep up with hot hatches OK. 40mpg average is about all you will manage, and around town it will take a dive.
If the geartronic ever goes wrong, there are plenty of specialist who can fix at a reasonable cost, as it is used on many other cars. Just don't go the engine remapped as the geartronic cannot handle the extra torque. Most D5s will be 7 years old + now as they stopped fitting it to the C70 in about 2010.
The D3 and D4 engines are very good, so maybe worth checking out.
In summary, the D3, D4 or D5 would be my choice if you want auto. 2.0D in a manual is OK, but I'd advise driving one to see if it has enough power.
Powershift too risky.
Enjoy your new car whatever you choose. Great value convertibles!!
PS move the thread to the general section for more feedback.