I have a bit of a soft spot for the Mundanos (not the early buckets, but from about 2004 onwards). However, colleagues who have had the current ones have had all sorts of electrical gremlins - instrumentation, DAB packing up, satnav not moving etc - which have either taken ages to get resolved, or never got resolved. Its possible the local dealer in MK is shit of course
For the Mundano v Insignia debate, I have driven a detuned, 130bhp CDTi Insignia to the France/Spain border and back, and it was an effortless, comfortable drive, with no reliability issues except running out of brakes on the way down. So I wouldn't be put off by an Insignia. I've also been a passenger in a Mundano from Luton to the home of Stella Artois, again no issues with comfort etc.... ....all issues on that lads weekend were purely down to trying too many of Belgiums finest