We have an '06 Knaus Sun Ti 650mf on a Renault Master chassis, which won the Motorhome of the Year award when first released. The build quality and winterisation features are excellent, and we think it is superb (though everyone thinks their choice is the best, don't they?).
However, something you need to know: Knaus themselves (who had been caravan manufacturers for years before moving into motorhomes) went bust and, after a period of uncertainty, were bought by Tabbert who are also long-standing German caravan manufacturers. It is felt they expanded too aggressively, setting up dealer networks in the UK etc., and were hit hard by the economic downturn.
Throughout this period it was very difficult to obtain spares and advice.
However, Tabbert have resurrected the Knaus brand, have released a range of new models, and things are now a lot easier.
The Knaus Owners Club www.knausowners.com
maintains links with Knaus Tabbert, and is a useful source of Knaus-related expertise and advice.
I don't have any direct experience of the latest Sun Ti range, though they would certainly be on my shortlist if I were to replace our 'van.
As always, it is the internal layout and features that are important. The '06 Sun Ti ticked all our boxes, and we love it.