Those head gaskets that were just replaced on the Subaru will probably need to be replaced again soon. They are notorious for that. That car has mostly engine problems. When I go to a place that snows, it seems like everyone has that generation of Outback. They are great in the snow and apparently last forever with proper maintenance. The 2.5 4 cyliner is more prone to blown head gaskets.
The 2005 Volvo V70 had some electrical issues and the earlier ones had some transmission failures, which is a $4k fix.
They are both unreliable, but the Subaru has lower repair costs so I'd go with the Subaru. Of course, an engine will be expensive to replace any way you go.
If you are willing to expand your research, test drive a Kia Soul. You could probably only afford a 2010, the first model. It has proven to be very reliable and much cheaper to fix, but it won't be as comfortable as the Outback or V70. It's very practical and will get better gas mileage than the other wagons. Doesn't have AWD, so that may be a deal breaker but you didn't say you needed it. It will probably be safer than the Outback with an added level of safety you get with a newer car. Plus, you will get much more mileage out of the Kia.