Just had a hire car, which was an Insignia. I've done over 1000 miles this week, and I feel like I've been carrying coal all week, boy oh boy does my back hurt... great car to drive, but a pain in the back, avoid please.
I drove a colleague's car after considering one for my next company car. Have to say I was very impressed. Currently drive a Mk6 VW Golf, so think it's fair to say refinement, build quality and dynamic ability isn't quite up there with its German competition, but as an honest, large, comfortable, motorway cruiser, I think Vauxhall have hit the mark with this car. It also drives quite nicely, and is worlds better than the Vectra it replaces. In 2.0 CDTi 160 Ecoflex form, it is also both quick, frugal and very clean.
One thing that has surprised me, and has led me to post this comment, is that I cannot believe people struggle to get comfortable behind the driver's seat. I was impressed with the range of adjustment in the driver's seat (electric height, manual base tilt and 4 way pneumatic lumber support) and found the seat itself a huge improvement on my Golf (which incidentally is a GT spec car with sports seats with lumber supports).
Also to the poster, later cars have active head restraints that are adjustable fore and aft as well as just the traditional up and down; maybe the restraint was pushed right out, and this is why you found it so uncomfortable?
I'm a private hire driver, and turn in between 12 -15 hours daily, and have to say that I find the Insignia very comfortable.
It is an auto, just like my Vectra was, and I think it's an improvement on the Vectra. I opted for the Exclusive model, simply for the softer suspension, and I didn't want the bucket type seats, so maybe that's the difference.