Today The Foundary is offering a sale on Kitchen Aid Mixers. I noticed that compare to what Rue La La is offering, The Foundary is offering the bigger models Artisan and Professional. I have a professional mixer and I can tell you the bowl is larger (6qts). I would say not everyone needs to have the larger bowls particularly if you plan on using them *very* occasionally. IF you are more of a baker and think you will use them often having the bigger bowl and heavier duty mixers is nice.
PLUS if you buy a Professional model for $299 + $5.95 shipping you can submit for this rebate offer (must purchase by 11/6) and get a free food grinder, ice cream maker or cheese slicer attachment. The professional sells for $349 on Amazon.