I went through the exact same thing as the OP. You are correct about the Volvo's being cheaper than the Lexus IS and Acura TL. As much as I love my Volvo, it's for a good reason.
The Lexus IS and TL are insanely reliable, and cost very little in maintenance and repair. Even a car as reliable as the Volvo T6 is still going to cost more to repair, as it's a European car.
I also looked at the TSX, but had to rule it out due to lack of horsepower. I knew that on a long road trip with 4 passengers, it was going to run out of breath, although it was probably the most fun to drive. The V6 TSX is very rare. As much as I love the IS250, it is extremely slow as well. The IS350 is a stellar pick, with ventilated seats and a good sound system, not to mention an extremely powerful V6. However, the entire market knows this, and they are expensive. The TL had good power, and I personally love the way the 2008 looks, but I would have been kicking myself for not getting the manual Type-S, and I couldn't find any for sale.
The 2012 S60 T6 is very comfortable, very attractive (especially with the RD rear end), and unlike any of the other cars, has AWD, which has been great for road trips. It's nearly as quick as the IS350, and for a 2012 has decent tech inside and audio. I'm happy with my choice.
Edit: I also considered the ES350, which is comfortable on a whole new level. However, due to the 3.5 V6, the car had terrible torque steer and handled like a battleship. The comfort factor was a 10/10 but driving was 1/10, even though it's quick in a straight line.