We have recently built a home with Medallion. We have one of Medallion exisitng design/display home (Urbis) tweaked to suit our personal preferences and size of the block. Our experiences with Medallion Homes are:
Positives:
Project completed on time;
Responsive to our questions/requests from Sales, Project Manager & Site Manager
Quickly rectified problems and issues (both raised by Site Manager and ourselves)
Good quality in some trades but not all trades.

Negatives:
Building costing- we have problems with the transparency of costing. There were many instances where we would have lost money either because they forgot to account for our initial deposit, charge for cost which have been included in the build contract had we not perused the costing in details. We had many variations to include extra items which are not in the spec.
Quality issue- There are a few issues relating to fiitings (eg wrong door handles installed), painting (doors are not completely painted, underside of doors in wet areas), doors contracted after installation and required replacement. We had a water leak inside the bathroom after the tiles were installed requiring extensive rework.
I visited the building site almost everyday to make sure I am happy with the work. One plus here is that the site manager responds to these issues quickly.
Post hand-over maintenance. It has certainly taken a long time. House was handed over in Feb 2012, we have not all maintenance issues rectified as at Sept 2013.

Overall, we are happy with the final products as we have followed the construction process to make sure we get what we pay for. We think it's expensive as we pay for the Medallion Homes Brand.

Be very wary of Medallion - we built with them in 2012 and know of 2 others who had the 'Medallion experience' in 2013. Very poor quality in both - plumbing needing to be replaced, ceiling redone and electrical problems. One removed Medallion from site and is still resolving problems. There's a growing number of very unhappy customers. Just ask Medallikn when they last won any of the building awards - back under previous ownership. Check out Alsn Shepard Homes, Scott Salisbury or even Metricon for a better experience.