Broken Supex SDX-1000 Repair or buy new?

The diamond came off of my vintage Supex SDX-1000 MC cartridge.  It'll be $650 to have it retipped and aligned (Northwest Analogue in the UK, I'm in the US) Should I spend that money on a modern cartridge instead of repairing it?  I can likely afford more than this for a modern MC cartridge. Anybody have experience with this cartridge as well as modern MC cartridges between $600-$1,000?   Thanks in advance for helping me.

PS Is there someone who retips cartridges who doesn't charge like this? Soundsmith in NY is worse. 

People have had good things to say about these guys in the Seattle area - both in terms of price and turnaround time - maybe give them a call?

Seems to me that only you can make this decision, based on your love or lack of love for the SDX1000.  If you love it very much, just try to get the re-tip as close as possible to the original, i.e., match the cantilever construction and the stylus shape to those of the original.  Personally, I always thought the SD900 was way over-rated, but I have never heard an SDX1000, and my opinion has nothing to do with this decision.  Also, contrary to what you wrote above, Sound Smith probably CAN do the re-tip for less than $600, maybe way less, depending upon your choice of cantilever and stylus shape.  Only issue with SS is that they may not be able to supply exact replacements for the cantilever/stylus.  On the other hand, their sapphire cantilever/OCL stylus shape sounds wonderful on my Grace Ruby.