You can DIY. That's a huge advantage, and changes the recommendation.
A new wax 'motor' might cost only $10, shipping included, on FleaBay. Replacing it takes much less time than installing a new dishwasher, especially if you consider you are likely to have minor fit and finish problems that will take extra time. (A professional install will just ignore gaps and an uneven fit, unless you pay top dollar.)
The reason to replace a dishwasher rather than fix it is when the liner cracks, the frame or door is rusting or the racks have a problem ($$$). If you are cheap, buy a replacement that has inexpensive part common across the whole product line rather than lowest upfront cost.