Hi Kelvin,
PC and the CC have tested the estate version and rated it pretty highly. PC compared it directly with the Volvo V70 and the Volvo only very narrowly came out top overall, they did concede however, that the 300c was a better actual towcar.
It has a lot going for it, high kerbweieght,ample max tow,a large powerful V6 diesel, rearwheel drive and economy of about 30mpg towing.
I was on a CL next to a Swift Conker towed by one of these last year and it certainly looked the biz, it seemed to haul the Swift, which must be almost 1900kg with no problems.
I think it would make a good alternative to a Merc e-class and probably about half the cost - It would be on my shortlist if I was in the market that's for sure!