Both quality machines but not exactly apples to apples. I had hoped to test the kubota KX91-3, but my dealer didn't have the smaller machine.

Volvo 37.0HP at 7470#, arm force 4923, bucket breakout 6564
Kubota 42.2HP at 9063#, arm force 3947, bucket breakout 8754

Aside from that, the specs for the two machines in terms of digging depth, lifting capacity, etc were remarkably similar.

Fit and finish were similar, with a slight nod to the Kubota for things like taking the time to place all the grease fittings on one side of the boom. The Volvo was much more robust however, in places it looked overbuilt (not that it's a bad thing), with larger cylinders and much more protection built in for those cylinders. I also found the Volvo better layed out for routine maintenance with extremely easy access to all filters, etc. And like the big rigs left overnight at construction sites it was more vandal proof which was a little inconvenient for a homeowner. Another clear difference was the extensive use of metal pipes for the Volvo hydraulics. From the manifold to the boom pivot point the Volvo's lines were neatly organized metal lines with precisely routed curves. The Kubota was a clustered chaos of rubber hoses taped or tied into bundles that looked like black spaghetti. I also liked the fact that the Volvo controls were an integrated part of the suspended seat, so as the seat moved over rough ground so did the joysticks. On the Kubota the seat had suspension but not the controls, so on hard jolts my hands were pulled off the joysticks.

Both were smooth, but the Kubota was better especially with fine movements; it felt like an extension of my arms. I also liked the way the Kubota switches were laid out, while the Volvo tucked different switches into odd places here and there. I'm sure five hours in the seat and I'd find the arrangement perfectly natural, but for me it would take some getting used to. Both were cab models. The Volvo had a wider door, but only the front half of the right hand window slid open. On the Kubota both halves of the window could be opened. The Volvo also only had heat, while the Kubota had full HVAC and better controls and air flow. Kubota uses an LCD display that was easy to read. Volvo uses an LED display that's hard to read because of glare.

The Kubota also had the angled blade. I didn't like it enough to buy, especially not for an extra $2k. While pushing a bit of snow across a parking lot with the blade angled, the blade pulled the entire excavator in that direction. Granted some of the problem may have been the icy surface, but it just didn't work for me.

So no clear winner, but a nod to Kubota.