Richard, I guess it depends on what you're going to do with it. There's a lot more to choosing a bag than just its filling weight and temperature rating. The design of baffles, zips, hoods etc makes a great difference to comfort levels, and the Snowline/Iceline series are MEs top of ther range series that have the best of everything. Mine gets used in British winters so the water resistant outer is essential, but still has the insulation and wind resistance I need when going to the Rockys, Pyrenees etc.
With top end kit, and especially ME kit I think you should always compromise on price rather than quality.....they don't make the Dragon series cheaper without compromising on performance/quality. Other than your boots you spend more time in your sleeping bag than any other piece of kit, and you want it to be comfortable and last.
