this is my suggestion : go to Consumers Report online & look for the most recent evaluation of dishwashers. You can pay a small fee to see that month's report - it will save you $$$ by getting access to that info OR even go to your local library & look in that month's issue.
I am sure you are familiar with Consumer's Report Magazine...(unbiased - doesn't accept any ads - performs testing & evaluating of products & reports on what are the top brands, reliability, various models, price ranges, repair record & features)
Then, armed with that info, you can go to your local appliance store & do some informed shopping on your specific needs/wants.
There are so many variations in dishwashers today -
what kind of cycles do you need/use,
do you want a built in disposal,
how many racks, where the heating elements are located,
what type of silverware tray & where it is located, on the door or rack, to what type of controls - dial, touch pad & where they are located, on outside front or hidden when door is shut....price range, whisper quiet, what color / cabintry front etc so I hesitate to recommend mine - as it may be something diferent than what you'd prefer.
I do think you would be better off buying a new one, than paying repair a 15 yr old one. Also, when you narrow your choice down, call around to get the best price that includes hauling the old one away & installing the new one. Many times you can also get a rebate with purchase.
Another tip, take your dinner plate with you & make sure it fits on the rack you'd place it...dumb huh? but my last house, I had a dishwasher put in & my plates couldn't stand up properly & so I wasn't able to put as many in as I wanted each wash...very irritating
Good Luck & have fun appliance shopping!!