I bought a new Volvo XC70 D5 SE (manual transmission) in the spring of this year and use it to tow a twin axle 1997 Bailey Senator 5000. This version of the XC70 comes with load compensating suspension as standard but it does not have the "Four C" actively controlled suspension fitted to the SE Lux. I have no direct experience of Volvo's "Four C" system, but it has received rather mixed reviews in the motoring press at various times and wonder if the "Four C" system is in any way having an adverse effect on the towing stability.
Previously, I towed this Senator 5000 since purchasing it new with a 1994 Vauxhall Omega 2.5 TD (automatic) saloon whose rear suspension was modified by fitting Monroe Ride Leveler shock absorbers. To date, I have completed over 2000 miles of towing with the Volvo. This included one very stormy day with strong crosswinds on French Autoroutes. Both cars have delivered similar and satisfactory but not outstanding levels of stability when towing and loaded with 2 adults and 3 teenage children. If anything the Omega had more "feel" in the steering, thus providing greater confidence.
As for performance, although fine solo and with the smaller caravan that I originally purchased it to tow, the Omega would have benefitted from more power when towing the twin axle Bailey. In comparison, the XC70 delivers greatly improved towing performance having substantially more torque and 40% more power than the Omega. As Allan and Gill put it above "power in reserve" even when towing over steep mountain passes. Noting that much of my driving is long distance not urban, with the Omega I typically achieved 35 to 40 MPG solo and 24 Mpg towing. The XC70 has delivered between 37 and 41 mpg solo and 26 mpg towing although at higher speeds when solo it drops off more markedly than the Omega - probably due to body shape and increased ground clearance.
The Omega served me well for many years including over 25000 miles of towing and I was sad to see it go. When choosing a replacement for the Omega, although I test drove a number of Discovery/Sorrento style full off-road vehicles, I was not keen to purchase one or another MPV (my other car is an MPV). My driving is predominantly on road, I do not need the capability offered by a full off-roader and prefer the handling of a conventional saloon/hatchback/estate. Nevertheless, the slightly higher ground clearance and limited 4 wheel drive capability provided by the XC70 have proved useful on a few occasions. Seating three adolescents in the rear in comfort, sufficient kerbweight and adequate power/torque left a small field of vehicles to chose from. Thus far, I am content with my choice of the XC70 as a towcar and would willingly recommend it to others with similar requirements.